Holtek HT45F23A User manual

TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A
HT45F24A
Revision: V1.40 Date: March 29, 2019

Rev. 1.40 2 March 29, 2019 Rev. 1.40 3 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Table of Contents
Features................................................................................................................. 7
CPU Features ............................................................................................................................... 7
Peripheral Features....................................................................................................................... 8
General Description.............................................................................................. 9
Selection Table...................................................................................................... 9
Block Diagram..................................................................................................... 10
Pin Assignment................................................................................................... 10
Pin Description ....................................................................................................11
Absolute Maximum Ratings............................................................................... 13
D.C. Characteristics............................................................................................ 13
A.C. Characteristics............................................................................................ 16
OP Amplier Electrical Characteristics ............................................................ 17
Comparator Electrical Characteristics ............................................................. 17
LDO 2.4V.............................................................................................................. 17
LDO 3.3V.............................................................................................................. 18
Power-on Reset Characteristics........................................................................ 18
System Architecture........................................................................................... 19
Clocking and Pipelining............................................................................................................... 19
Program Counter......................................................................................................................... 20
Stack ........................................................................................................................................... 21
Arithmetic and Logic Unit – ALU ................................................................................................. 21
Flash Program Memory...................................................................................... 22
Structure...................................................................................................................................... 22
Special Vectors ........................................................................................................................... 22
Look-up Table.............................................................................................................................. 23
Table Program Example.............................................................................................................. 24
In Circuit Programming ............................................................................................................... 25
RAM Data Memory .............................................................................................. 26
Structure...................................................................................................................................... 27
Special Function Registers................................................................................ 27
Indirect Addressing Registers – IAR0, IAR1 ............................................................................... 28
Memory Pointers – MP0, MP1 .................................................................................................... 28
Bank Pointer – BP....................................................................................................................... 29
Accumulator – ACC..................................................................................................................... 29
Program Counter Low Register – PCL........................................................................................ 30
Look-up Table Registers – TBLP, TBHP, TBLH........................................................................... 30
Status Register – STATUS.......................................................................................................... 30

Rev. 1.40 2 March 29, 2019 Rev. 1.40 3 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
EEPROM Data Memory....................................................................................... 32
EEPROM Data Memory Structure .............................................................................................. 32
EEPROM Registers .................................................................................................................... 32
Reading Data from the EEPROM ............................................................................................... 34
Writing Data to the EEPROM...................................................................................................... 34
Write Protection........................................................................................................................... 34
EEPROM Interrupt ...................................................................................................................... 34
Programming Considerations...................................................................................................... 35
Programming Examples.............................................................................................................. 35
Oscillator ............................................................................................................. 36
Oscillator Overview ..................................................................................................................... 36
System Clock Congurations ...................................................................................................... 36
External Crystal/ Ceramic Oscillator – HXT ................................................................................ 37
External RC Oscillator – ERC ..................................................................................................... 38
External Oscillator – EC .............................................................................................................. 39
Internal RC Oscillator – HIRC ..................................................................................................... 39
External 32.768kHz Crystal Oscillator – LXT .............................................................................. 39
LXT Oscillator Low Power Function ............................................................................................ 40
Internal 32kHz Oscillator – LIRC................................................................................................. 40
Supplementary Oscillators .......................................................................................................... 40
Operating Modes and System Clocks .............................................................. 41
System Clocks ............................................................................................................................ 41
System Operation Modes............................................................................................................ 41
Control Register .......................................................................................................................... 44
Fast Wake-up.............................................................................................................................. 45
Operating Mode Switching and Wake-up.................................................................................... 46
Standby Current Considerations ................................................................................................. 50
Wake-up...................................................................................................................................... 51
Programming Considerations...................................................................................................... 51
Watchdog Timer.................................................................................................. 52
Watchdog Timer Clock Source.................................................................................................... 52
Watchdog Timer Control Register ............................................................................................... 52
Watchdog Timer Operation ......................................................................................................... 53
Reset and Initialisation....................................................................................... 54
Reset Functions .......................................................................................................................... 54
Reset Initial Conditions ............................................................................................................... 57
Input/Output Ports .............................................................................................. 60
Pull-high Resistors ...................................................................................................................... 60
Port A Wake-up ........................................................................................................................... 60
I/O Port Control Registers ........................................................................................................... 60
I/O Pin Structures........................................................................................................................ 62
Programming Considerations...................................................................................................... 62

Rev. 1.40 4 March 29, 2019 Rev. 1.40 5 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Timer/Event Counters ........................................................................................ 64
Conguring the Timer/Event Counter Input Clock Source .......................................................... 64
Timer Registers – TMR0, TMR1L, TMR1H ................................................................................. 64
Timer Control Registers – TMR0C, TMR1C................................................................................ 66
Conguring the Timer Mode........................................................................................................ 66
Conguring the Event Counter Mode.......................................................................................... 67
Conguring the Pulse Width Measurement Mode....................................................................... 67
Programmable Frequency Divider – PFD ................................................................................... 69
Prescaler ..................................................................................................................................... 69
I/O Interfacing.............................................................................................................................. 72
Timer/Event Counter Pins Internal Filter ..................................................................................... 72
Programming Considerations...................................................................................................... 72
Timer Program Example ............................................................................................................. 73
Pulse Width Modulator....................................................................................... 74
PWM Operation........................................................................................................................... 74
6+2 PWM Mode .......................................................................................................................... 75
7+1 PWM Mode .......................................................................................................................... 76
PWM Output Control ................................................................................................................... 77
Analog to Digital Converter ............................................................................... 78
A/D Overview .............................................................................................................................. 78
A/D Converter Register Description ............................................................................................ 79
A/D Converter Data Registers – ADRL, ADRH ........................................................................... 79
A/D Converter Control Registers – ADCR, ACSR, ADPCR ........................................................ 79
A/D Operation ............................................................................................................................. 83
A/D Input Pins ............................................................................................................................. 84
Summary of A/D Conversion Steps............................................................................................. 85
Programming Considerations...................................................................................................... 86
A/D Transfer Function ................................................................................................................. 86
A/D Programming Example......................................................................................................... 87
Serial Interface Module – SIM ............................................................................ 89
SPI Interface ............................................................................................................................... 89
SPI Registers .............................................................................................................................. 90
SPI Communication .................................................................................................................... 93
I2C Interface ................................................................................................................................ 95
I2C Registers ............................................................................................................................... 96
I2C Bus Communication ............................................................................................................ 100
I2C Bus Start Signal................................................................................................................... 101
I2C Bus Read/Write Signal ........................................................................................................ 102
I2C Bus Slave Address Acknowledge Signal............................................................................. 102
I2C Bus Data and Acknowledge Signal ..................................................................................... 102
Peripheral Clock Output................................................................................... 104
Peripheral Clock Operation ....................................................................................................... 104

Rev. 1.40 4 March 29, 2019 Rev. 1.40 5 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
SCOM Function for LCD................................................................................... 105
LCD Operation .......................................................................................................................... 105
LCD Bias Control ...................................................................................................................... 105
LDO Function ............................................................................................................................ 107
Operational Ampliers ..................................................................................... 109
Operational Amplier Registers................................................................................................. 109
Operational Amplier Operation .................................................................................................111
Operational Amplier Functions .................................................................................................112
Comparators ......................................................................................................116
Comparator Operation ...............................................................................................................116
Comparator Registers ................................................................................................................116
Comparator Functions................................................................................................................118
Interrupts ........................................................................................................... 121
Interrupt Register ...................................................................................................................... 121
Interrupt Operation .................................................................................................................... 121
Interrupt Priority......................................................................................................................... 122
External Interrupt....................................................................................................................... 125
External Peripheral Interrupt ..................................................................................................... 127
Timer/Event Counter Interrupt................................................................................................... 127
SPI/I2C Interface Interrupt ......................................................................................................... 128
Multi-function Interrupt .............................................................................................................. 128
A/D Interrupt.............................................................................................................................. 128
Time Base Interrupt................................................................................................................... 129
Comparator Interrupt................................................................................................................. 130
EEPROM Interrupt .................................................................................................................... 130
LVD Interrupt ............................................................................................................................. 130
Interrupt Wake-up Function....................................................................................................... 130
Programming Considerations.................................................................................................... 131
Buzzer ................................................................................................................ 131
Low Voltage Detector – LVD ............................................................................ 133
LVD Register ............................................................................................................................. 133
LVD Operation........................................................................................................................... 134
Voice Output...................................................................................................... 135
Voice Control............................................................................................................................. 135
Audio Output and Volume Control – DAL, DAH, DACTRL ....................................................... 135
Conguration Options...................................................................................... 136
Application Circuits.......................................................................................... 137

Rev. 1.40 6 March 29, 2019 Rev. 1.40 7 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Instruction Set................................................................................................... 138
Introduction ............................................................................................................................... 138
Instruction Timing ...................................................................................................................... 138
Moving and Transferring Data................................................................................................... 138
Arithmetic Operations................................................................................................................ 138
Logical and Rotate Operation ................................................................................................... 139
Branches and Control Transfer ................................................................................................. 139
Bit Operations ........................................................................................................................... 139
Table Read Operations ............................................................................................................. 139
Other Operations....................................................................................................................... 139
Instruction Set Summary ................................................................................. 140
Table Conventions..................................................................................................................... 140
Instruction Denition........................................................................................ 142
Package Information ........................................................................................ 151
16-pin NSOP(150mil) Outline Dimensions................................................................................ 152
20-pin SSOP (150mil) Outline Dimensions ............................................................................... 153
24-pin SSOP (150mil) Outline Dimensions ............................................................................... 154
28-pin SSOP (150 mil) Outline Dimensions .............................................................................. 155

Rev. 1.40 6 March 29, 2019 Rev. 1.40 7 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Features
CPU Features
• Operating voltage
♦fSYS= 32.768kHz: 2.2V~5.5V
♦fSYS= 910kHz: 2.2V~5.5V
♦fSYS= 2MHz: 2.2V~5.5V
♦fSYS= 4MHz: 2.2V~5.5V
♦fSYS= 8MHz: 3.3V~5.5V
• TinyPowerTM technology for low power operation
• Power down and wake-up functions to reduce power consumption
• Oscillator types
♦External Crystal – HXT
♦External 32.768kHz Crystal – LXT
♦External RC – ERC
♦Internal RC – HIRC
♦Internal 32kHz RC – LIRC
♦External Clock – EC
• Multi-mode operation: Normal, Slow, Idle and Sleep
• Fully integrated internal 32kHz, 910kHz, 2MHz, 4MHz and 8MHz oscillator requires no external
components
• Externally supplied system clock option
• All instructions executed in one or two machine cycles
• Table read instructions
• 61 or 63 powerful instructions
• 6-level subroutine nesting
• Bit manipulation instruction

Rev. 1.40 8 March 29, 2019 Rev. 1.40 9 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Peripheral Features
• Flash Program Memory: 2K×15~4K×16
• RAM Data Memory: 128×8~192×8
• True EEPROM Memory: 64×8
• Up to 26 bidirectional I/O lines
• Watchdog Timer function
• Software controlled 4-SCOM lines LCD COM driver with 1/2 bias
• Multiple pin-shared external interrupts
• Single 8-bit programmable Timer/Event Counter with overow interrupt and Single 16-bit
programmable Timer/Event Counter with overow interrupt function
• Dual Time-Base functions
• Serial Interfaces Module – SIM for SPI or I2C
• Dual Comparator functions
• Dual Operational Ampliers functions
• Operational Amplier output to internal two channel 12-bit ADC function
• Multi-channel 12-bit ADC
• Up to 2 channel 8-bit PWM
• 12-bit Audio DAC output
• PFD/Buzzer for audio frequency generation
• Internal 2.4V/3.3V LDO
• Low voltage reset function
• Low voltage detect function
• 16-pin NSOP, 20/24/28-pin SSOP package types

Rev. 1.40 8 March 29, 2019 Rev. 1.40 9 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
General Description
The HT45F23A and HT45F24A are Flash Memory Tinypower A/D type 8-bit high performance
RISC architecture microcontrollers, designed especially for applications that interface directly to
analog signals. The devices have higher gain bandwidth making them more suitable for higher
frequency applications.
Offering users the convenience of Flash Memory multi-programming features, the devices also
include wide range of functions and features. Other memory includes an area of RAM Data Memory
as well as an area of true EEPROM memory for storage of non-volatile data such as serial numbers,
calibration data etc.
Analog features include an integrated multi-channel Analog to Digital Converter, dual Pulse Width
Modulation outputs, dual Operational Ampliers, dual Comparators, one internal 2.4V or 3.3V LDO
(Low Drop Out) for voltage regulator and a 12-bit DAC for voice output application, communication
with the outside world is catered for by including fully integrated SPI or I2C interface functions,
two popular interfaces which provide designers with a means of easy communication with external
peripheral hardware. Protective features such as an internal Watchdog Timer, Low Voltage Reset
and Low Voltage Detector coupled with excellent noise immunity and ESD protection ensure that
reliable operation is maintained in hostile electrical environments.
A full choice of internal, external, low and high speed oscillator functions are provided including
fully integrated system oscillators which require no external components for their implementation.
The unique Holtek TinyPower technology also gives the devices extremely low current consumption
characteristics, an extremely important consideration in the present trend for low power battery
powered applications. The usual Holtek MCU features such as power down and wake-up functions,
oscillator options, programmable frequency divider, etc. combine to ensure user applications require
a minimum of external components.
The inclusion of exible I/O programming features, Time-Base functions along with many other
features ensure that the devices will find excellent use in applications such as smoke detectors,
electronic metering, environmental monitoring, handheld instruments, household appliances,
electronically controlled tools, motor driving, home security systems and many others.
Selection Table
Part No. Program Memory Data Memory Data EEPROM I/O Ext. Interrupt
HT45F23A 2K×15 128×8 64×8 22 2
HT45F24A 4K×16 192×8 64×8 26 2
Part No. A/D Timer Time Base Stack Package
HT45F23A 12-bit×6 8-bit×1
16-bit×1 2 6 16NSOP 20/24SSOP
HT45F24A 12-bit×8 8-bit×1
16-bit×1 2 6 20/24/28SSOP

Rev. 1.40 10 March 29, 2019 Rev. 1.40 11 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Block Diagram
8-bit
RISC
MCU
Core
LCD
Driver
Flash
Program
Memory
EEPROM
Data
Memory
Flash/EEPROM
Programming Circuitry
Time
Base
PFD/Buzzer
Driver
Low Voltage
Reset
Watchdog
Timer
Low Voltage
Detect
Interrupt
Controller
Reset
Circuit
External
Oscillators
12-bit A/D
Converter
RAM Data
Memory
ICP
Internal RC
Oscillators
Comparators
PWM
Generator
D/A
Converter
I/O SIM Timers OPAs
LDO
Pin Assignment
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


Rev. 1.40 10 March 29, 2019 Rev. 1.40 11 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Pin Description
Pin Name Function OPT I/T O/T Description
PA0/CNP/SCOM0
PA0 PAPU
PAWU ST CMOS General purpose I/O. Register enabled pull-up, wake-up
CNP CMP1C1 CMPI — Comparator input pin
SCOM0 LCDC — SCOM Software controlled 1/2 bias LCD COM
PA1/C1OUT/TC0
PA1 PAPU
PAWU ST CMOS General purpose I/O. Register enabled pull-up, wake-up
C1OUT CMP1C1 — CMPO Comparator 1 output pin
TC0 — ST — External Timer 0 clock input
PA2/A1P/C2OUT
PA2 PAPU
PAWU ST CMOS General purpose I/O. Register enabled pull-up, wake-up
A1P OPA1C1 OPAI — OPA1 non-inverting input pin
C2OUT CMP2C1 — CMPO Comparator 2 output pin
PA3/A1N/INT0
PA3 PAPU
PAWU ST CMOS General purpose I/O. Register enabled pull-up, wake-up
A1N OPA1C1 OPAI — OPA1 inverting input pin
INT0 — ST — External interrupt 0 input pin
PA4/A1E/TC1
PA4 PAPU
PAWU ST CMOS General purpose I/O. Register enabled pull-up, wake-up
A1E OPA1C1 — OPAO OPA1 output pin
TC1 — ST — External Timer 1 clock input
PA5/A2P/PFD
PA5 PAPU
PAWU ST CMOS General purpose I/O. Register enabled pull-up, wake-up
A2P OPA2C1 OPAI — OPA2 non-inverting input pin
PFD MISC — CMOS PFD output
PA6/A2N/BZ
PA6 PAPU
PAWU ST CMOS General purpose I/O. Register enabled pull-up, wake-up
A2N OPA2C1 OPAI — OPA2 inverting input pin
BZ BPCTL — CMOS Buzzer output
PA7/A2E/BZ
PA7 PAPU
PAWU ST CMOS General purpose I/O. Register enabled pull-up, wake-up
A2E OPA2C1 — OPAO OPA2 output pin
BZ BPCTL — CMOS Complementary buzzer output
PB0/SDO/INT1
PB0 PBPU
MISC ST CMOS NMOS
General purpose I/O. Register enabled pull-up and
output NMOS structure.
SDO — — CMOS SPI data output
INT1 — ST — External interrupt 1 input pin
PB1/SDI/SDA
PB1 PBPU
MISC ST CMOS NMOS
General purpose I/O. Register enabled pull-up and
output NMOS structure.
SDI — ST — SPI data input
SDA — ST NMOS I2C data
PB2/SCK/SCL
PB2 PBPU
MISC ST CMOS NMOS
General purpose I/O. Register enabled pull-up and
output NMOS structure.
SCK — ST — SPI serial clock
SCL — ST NMOS I2C clock
PB3/AN0/SCS
PB3 PBPU
MISC ST CMOS NMOS
General purpose I/O. Register enabled pull-up and
output NMOS structure.
AN0 ADCR AN — A/D channel 0
SCS — ST — SPI slave select

Rev. 1.40 12 March 29, 2019 Rev. 1.40 13 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Pin Name Function OPT I/T O/T Description
PB4/AN1/AUD/PCK
PB4 PBPU ST CMOS General purpose I/O. Register enabled pull-up
AN1 ADCR AN CMOS A/D channel 1
AUD DACTRL — — D/A output pin
PCK — — CMOS Peripheral clock output
PB5/AN2/PINT
PB5 PBPU ST CMOS General purpose I/O. Register enabled pull-up
AN2 ADCR AN — A/D channel 2
PINT — ST — Peripheral interrupt
PB6/AN3/RES
PB6 PBPU ST CMOS General purpose I/O. Register enabled pull-up
AN3 ADCR AN — A/D channel 3
RES CO ST — Reset pin
PB7 PB7 PBPU ST CMOS General purpose I/O. Register enabled pull-up
PC0/AN4/OSC2
PC0 PCPU ST CMOS General purpose I/O. Register enabled pull-up
AN4 ADCR AN — A/D channel 4
OSC2 CO — HXT HXT pin
PC1/AN5/OSC1
PC1 PCPU ST CMOS General purpose I/O. Register enabled pull-up
AN5 ADCR AN — A/D channel 5
OSC1 CO HXT — HXT/ERC pin
PC2/XT1 PC2 PCPU ST CMOS General purpose I/O. Register enabled pull-up
XT1 CO LXT — LXT pin
PC3/XT2 PC3 PCPU ST CMOS General purpose I/O. Register enabled pull-up
XT2 CO — LXT LXT pin
PC4/VREF/VCAP/
SCOM1
PC4 PCPU ST CMOS General purpose I/O. Register enabled pull-up
VREF ACSR AN — ADC reference input
VCAP LDOC — — LDO output capacitor pin. Connect a 0.1µF capacitor
SCOM1 LCDC — SCOM Software controlled 1/2 bias LCD COM
PC5/PWM0/C1N/
SCOM2
PC5 PCPU ST CMOS General purpose I/O. Register enabled pull-up
PWM0 BPCTL — CMOS PWM0 output pin
C1N CMP1C1 CMPI — Comparator 1 inverting input pin
SCOM2 LCDC — SCOM Software controlled 1/2 bias LCD COM
PC6/PWM1/C2P/
SCOM3
PC6 PCPU ST CMOS General purpose I/O. Register enabled pull-up
PWM1 BPCTL — CMOS PWM1 output pin
C2P CMP2C1 CMPI — Comparator 2 non-inverting input pin
SCOM3 LCDC — SCOM Software controlled 1/2 bias LCD COM
PC7 PC7 PCPU ST CMOS General purpose I/O. Register enabled pull-up
PD0/AN6 PD0 PDPU ST CMOS General purpose I/O. Register enabled pull-up
AN6 ADCR AN — A/D channel 6
PD1/AN7 PD1 PDPU ST CMOS General purpose I/O. Register enabled pull-up
AN7 ADCR AN — A/D channel 7
VDD VDD — PWR — Power supply
VSS VSS — PWR — Ground
Note: I/T: Input type; O/T: Output type
OPT: Optional by conguration option (CO) or register option
PWR: Power; CO: Conguration option
ST: Schmitt Trigger input; DAO: D/A output
CMOS: CMOS output; SCOM: Software controlled LCD COM
HXT: High frequency crystal oscillator; LXT: Low frequency crystal oscillator
OPAI: Operational Amplier input; OPAO: Operational Amplier output
CMPI: Comparator input; CMPO: Comparator output; AN: Analog input
PB7,PC7,PD0/AN6 and PD1/AN7 lines, for the HT45F24A only

Rev. 1.40 12 March 29, 2019 Rev. 1.40 13 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Absolute Maximum Ratings
Supply Voltage ................................................................................................VSS−0.3V to VSS+6.0V
Input Voltage ..................................................................................................VSS−0.3V to VDD+0.3V
Storage Temperature....................................................................................................-50˚C to 125˚C
Operating Temperature..................................................................................................-40˚C to 85˚C
IOL Total ................................................................................................................................... 100mA
IOH Total..................................................................................................................................-100mA
Total Power Dissipation ......................................................................................................... 500mW
Note: These are stress ratings only. Stresses exceeding the range specified under "Absolute Maximum
Ratings" may cause substantial damage to these devices. Functional operation of these devices at
other conditions beyond those listed in the specication is not implied and prolonged exposure to
extreme conditions may affect devices reliability.
D.C. Characteristics
Ta=25˚C
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VDD Conditions
VDD Operating Voltage —
fSYS=910kHz,
(HXT/ERC/HIRC) 2.2 — 5.5 V
fSYS=2MHz,
(HXT/ERC/HIRC) 2.2 — 5.5 V
fSYS=4MHz,
(HXT/ERC/HIRC/EC) 2.2 — 5.5 V
fSYS=8MHz
(HXT/ERC/HIRC/EC) 3.3 — 5.5 V
IDD1
Operating Current
(HXT, ERC)
3.3V
No load, fSYS=fM=455kHz,
ADC off, LVR off,
Comparator off, OPAs off
— 70 110 µA
Operating Current
(HXT, ERC)
No load, fSYS=fM= 455kHz,
ADC off, LVR on,
Comparator on, OPAs off
— 100 150 µA
IDD2
Operating Current
(ERC, HIRC)
3.3V
No load, fM=910kHz,
fSYS=fSLOW=455kHz,
ADC off, LVR off,
Comparator off, OPAs off
— 90 135 µA
Operating Current
(ERC, HIRC)
No load, fM=910kHz,
fSYS=fSLOW=455kHz,
ADC off, LVR on,
Comparator on, OPAs off
— 120 180 µA
IDD3
Operating Current
(ERC, HIRC)
3.3V
No load, fSYS=fM=910kHz,
ADC off, LVR off,
Comparator off, OPAs off
—110 170 µA
Operating Current
(ERC, HIRC)
No load, fSYS=fM=910kHz,
ADC off, LVR on,
Comparator on, OPAs off
— 160 240 µA
IDD4
Operating Current
(HXT, ERC)
3.3V
No load, fSYS=fM=1MHz,
ADC off, LVR off,
Comparator off, OPAs off
— 120 180 µA
Operating Current
(HXT, ERC)
No load, fSYS=fM=1MHz,
ADC off, LVR on,
Comparator on, OPAs off
— 170 260 µA

Rev. 1.40 14 March 29, 2019 Rev. 1.40 15 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VDD Conditions
IDD5
Operating Current
(HXT, ERC, HIRC)
3.3V
No load, fSYS=fM=2MHz,
ADC off, LVR off,
Comparator off, OPAs off
— 170 260 µA
Operating Current
(HXT, ERC, HIRC)
No load, fSYS=fM=2MHz,
ADC off, LVR on,
Comparator on, OPAs off
— 200 300 µA
IDD6
Operating Current
(HXT, ERC, HIRC)
3V No load, fSYS=fM=4MHz,
ADC off
— 420 630 µA
5V — 700 1000 µA
IDD7
Operating Current
(EC)
3V No load, fSYS=fM=4MHz,
ADC off
— 330 500 µA
5V — 550 820 µA
IDD8
Operating Current
(HXT, ERC, HIRC) 5V No load, fSYS=fM=8MHz, ADC off — 1.5 3.0 mA
IDD9
Operating Current (Slow Mode,
fM=4MHz) (HXT, ERC, HIRC)
3V No load, fSYS=fSLOW=1MHz,
ADC off
— 200 300 µA
5V — 400 600 µA
IDD10
Operating Current (Slow Mode,
fM=4MHz) (HXT, ERC, HIRC)
3V No load, fSYS=fSLOW=2MHz,
ADC off
— 250 375 µA
5V — 560 840 µA
IDD11
Operating Current (Slow Mode,
fM=8MHz) (HXT, ERC, HIRC)
3V No load, fSYS=fSLOW=2MHz,
ADC off
— 300 450 µA
5V — 680 1020 µA
IDD12
Operating Current (Slow Mode,
fM=8MHz) (HXT, ERC, HIRC)
3V No load, fSYS=fSLOW=4MHz,
ADC off
— 450 800 µA
5V — 1000 1500 µA
IDD13
Operating Current
(fSYS=LXT note 1 or LIRC)
3V No load, WDT off, ADC off — 10 20 µA
5V — 20 35 µA
ISTB1
Standby Current (Sleep)
(fSYS, fSUB, fS, fWDT=off)
3V No load, system HALT,
WDT off
— 0.1 1.0 µA
5V — 0.2 2.0 µA
ISTB2
Standby Current (Sleep)
(fSYS Off; fSOn;
fWDT=fSUB=LXT note 1 or LIRC)
3V No load, system HALT,
WDT on
— 1.5 3.0 µA
5V — 2.5 5.0 µA
ISTB3
Standby Current (Idle)
(fSYS Off; fWDT Off; fS=fSUB=LXTnote 1 or LIRC)
3V No load, system HALT,
WDT off
— 4 6 µA
5V — 6 9 µA
ISTB4
Standby Current (Idle)
(fSYS On, fSYS=fM=4MHz; fWDT Off;
fS=fSUB=LXT note 1 or LIRC)
3V No load, system HALT,
WDT off, SPI or I2C on,
PCK on, fPCK=fSYS/8
— 260 350 µA
5V — 350 660 µA
VIL1 Input Low Voltage for I/O, TCn and INTn — — 0 — 0.3VDD V
VIH1 Input High Voltage for I/O, TCn and INTn — — 0.7VDD — VDD V
VIL2 Input Low Voltage (RES) — — 0 — 0.4VDD V
VIH2 Input High Voltage (RES) — — 0.9VDD — VDD V
VIL3 Input Low Voltage (PB1~PB3) 5V — — — 1 V
VIH3 Input High Voltage (PB1~PB3) 5V — 2 — — V
VLVR1
Low Voltage Reset —
VLVR=2.10V
-5%
2.10
+5% V
VLVR2 VLV R=2.55V 2.55
VLVR3 VLV R=3.15V 3.15
VLVR4 VLV R=4.20V 4.20

Rev. 1.40 14 March 29, 2019 Rev. 1.40 15 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VDD Conditions
VLVD1
Low Voltage Detector Voltage —
LVDEN=1, VLVD=2.0V
-5%
2.0
+5% V
VLVD2 LVDEN=1, VLV D=2.2V 2.2
VLVD3 LVDEN=1, VLV D=2.4V 2.4
VLVD4 LVDEN=1, VLV D=2.7V 2.7
VLVD5 LVDEN=1, VLV D=3.0V 3.0
VLVD6 LVDEN=1, VLV D=3.3V 3.3
VLVD7 LVDEN=1, VLV D=3.6V 3.6
VLVD8 LVDEN=1, VLV D=4.4V 4.4
IOL I/O Port Sink Current 3V VOL=0.1VDD
6 12 — mA
5V 10 25 — mA
IOH I/O Port Source Current 3V VOH=0.9VDD
-2 -4 — mA
5V -5 -8 — mA
RPH Pull-high Resistance 3V — 40 60 80 kΩ
5V — 10 30 50 kΩ
AVDD A/D Converter Operating Voltage — — 2.7 — 5.5 V
VAD A/D Input Voltage — — 0 — VREF V
VREF A/D Input Reference Voltage Range — AVDD=5V 2 — VDD V
DNL ADC Differential Non-Linearity 3V VREF=VDD, tAD=1µs — ±1 ±2 LSB
5V
INL ADC Integral Non-Linearity 3V VREF=VDD, tAD=1µs — ±2 ±4 LSB
5V
IADC
Additional Power Consumption
if A/D Converter is Used
3V — — 0.5 1.0 mA
5V — — 1.5 3.0 mA
VBG
Bandgap Reference with Buffer
voltage — — -3% 1.25 +3% V
ILVR
DC current when LVR or LVD
turn on
3V —— 10 15 µA
5V — 20 30 µA
VSCOM
VDD/2 Voltage for LCD COM 5V No load 0.475 0.500 0.525 VDD
VLDO/2 Voltage for LCD COM 5V No load 0.475 0.500 0.525 VLDO
IOUT Output Current 5V
ISEL=0, LCDBUF=0 — 10 — µA
ISEL=1, LCDBUF=0 — 25 — µA
ISEL=0, LCDBUF=1 — 2 — mA
ISEL=1, LCDBUF=1 — 2 — mA
Note: 1. tSYS= 1/fSYS; tSUB = 1/fSUB
2. Detailed showing please refer LDO section.

Rev. 1.40 16 March 29, 2019 Rev. 1.40 17 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
A.C. Characteristics
Ta=25˚C
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VDD Conditions
fSYS1
System Clock
(HXT, ERC, HIRC) —2.2V~5.5V 400 — 4000 kHz
3.3V~5.5V 400 — 8000 kHz
fSYS2 8MHz HIRC
3.3V Ta=25˚C -2% 8 +2% MHz
3.3V Ta=-40~85˚C -5% 8 +5% MHz
2.7V~5.5V Ta=-40~85˚C -10% 8 +10% MHz
fSYS3 4MHz HIRC
3.3V Ta=25˚C -2% 4 +2% MHz
3.3V Ta=-40~85˚C -5% 4 +5% MHz
2.7V~5.5V Ta=-40~85˚C -10% 4 +10% MHz
fSYS4 2MHz HIRC
3.3V Ta=25˚C -2% 2 +2% MHz
3.3V Ta=-40~85˚C -5% 2 +5% MHz
2.7V~5.5V Ta=-40~85˚C -10% 2 +10% MHz
fSYS5 910kHz HIRC
3.3V Ta=25˚C -2% 0.91 +2% MHz
3.3V Ta=-40~85˚C -5% 0.91 +5% MHz
2.7V~5.5V Ta=-40~85˚C -10% 0.91 +10% MHz
fLXT System Clock (LXT) — — — 32.768 — kHz
fERC 4MHz ERC (Note 3)
3.3V R=150kΩ, Ta=25˚C -2% 4 +2% MHz
3.3V R=150kΩ, Ta=-40~85˚C -8% 4 +8% MHz
2.7V~5.5V R=150kΩ, Ta=-40~85˚C -15% 4 +15% MHz
tLIRC 32kHz RC Period 3V — 28.10 31.25 34.40 µs
tRES External Reset Low Pulse Width — — 1 — — µs
tLVR Low Voltage width to Reset — — 60 120 240 µs
tLVD Low Voltage width to Interrupt — — 60 120 240 µs
tLVDS LVDO Stable Time 5V LVR disable, LVD enable,
VBG is ready — — 100 µs
tRSTD
System Reset Delay Time
(Power-on Reset) — — — 100 — ms
tSST1
System start-up timer period
(W/O fast start-up) of HXT/TBC —Power up or wake-up from Sleep mode — 1024 — tSYS* note 1
tSST2
System start-up timer period of
ERC, HIRC, EC —Power up or wake-up from HALT (Idle or Sleep mode) — 1 2 tSYS
tSST3
System start-up timer period
(With fast start-up) of HXT/TBC —wake-up from Idle mode (fSL=fTBC)
— 1 2 tTBC note 2
tSST4
System start-up timer period
(With fast start-up) of HXT/TBC —wake-up from Idle mode (fSL=fLIRC)— 1 2 tLIRC
tINT Interrupt Pulse Width — — 1 — — µs
tAD A/D Clock Period — — 0.5 — — µs
tADC A/D Conversion Time Note 4 — — — 16 — tAD
tON2ST A/D on to A/D Start — 2.2V~5.5V 2 — — µs
Note: 1. tSYS=1/fSYS; tSUB=1/fSUB
2. tTBC is period of LXT or LIRC and it will not stop at Idle mode.
3. For fERC, as the resistor tolerance will inuence the frequency a precision resistor is recommended.
4. ADC conversion time (tAD)=n (bits ADC) + 4 (sampling time). The conversion for each bit needs one
ADC clock (tAD).

Rev. 1.40 16 March 29, 2019 Rev. 1.40 17 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
OP Amplier Electrical Characteristics
Ta=25˚C
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VDD Conditions
D.C. Characteristic
VDD Operating voltage — — 2.2 — 5.5 V
IDD Quiescent current 5V No load, A1OEN/A2OEN xed to 0 — 200 350 µA
VOPOS Input offset voltage 5V — -5 — +5 mV
IOPOS Input offset current — VDD=5V, VCM=1/2VDD, Ta=-40~85˚C — 10 — nA
VCM Common Mode Voltage Range — — VSS — VDD-1.4 V
PSRR Power Supply Rejection Ratio — — 58 80 — dB
CMRR Common Mode Rejection Ratio — VDD=5V, VCM=0~VDD-1.4V 58 80 — dB
A.C. Characteristic
AOL Open Loop Gain — — 60 80 — dB
SR Slew Rate+, Rate — No load — 0.1 — V/µs
GBW Gain Band Width — RL=1MΩ, CL=100pF 1 2 — MHz
Comparator Electrical Characteristics
Ta=25˚C
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VDD Conditions
VDDC Comparator Operating Voltage — — 2.2 — 5.5 V
IDDC Comparator Operating Current 3V —— 20 40 µA
5V — 30 60 µA
VCPOS1 Comparator Input Offset Voltage 5V CxOF[4:0]=10000 -10 — +10 mV
VCPOS2 Comparator Input Offset Voltage 5V By calibration -4 — +4 mV
VCM Comparator Common Mode Voltage Range — — VSS — VDD-1.4 V
AOL Comparator Open Loop Gain — — 60 80 — dB
tPD1 Comparator Response Time — With 2mV overdrive — — 2 µs
tPD2 Comparator Response Time — With 10mV overdrive — — 1.5 µs
LDO 2.4V
Ta=25˚C
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VDD Conditions
VDDIN Supply Voltage — — 2.7 — 5.5 V
VDDOUT Output Voltage — — 2.28 2.40 2.52 V
IDD Current Consumption — After startup, no load — 50 70 µA
IOUT Output Current 5V VCAP=1µF 200 — 1100 µA
tSTART LDO Turn On Stable Time 5V VCAP=10uF — — 1600 ms

Rev. 1.40 18 March 29, 2019 Rev. 1.40 19 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
LDO 3.3V
Ta=25˚C
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VDD Conditions
VDDIN Supply Voltage — — 3.6 — 5.5 V
VDDOUT Output Voltage — — 3.13 3.30 3.46 V
IDD Current Consumption — After startup, no load — 50 70 µA
IOUT Output Current 5V VCAP=1µF 200 — 1100 µA
tSTART LDO Turn On Stable Time 5V VCAP=10uF — — 1600 ms
Note: 1.This LDO can provide stable power supply for PIR sensor with a 10µF cap.
2. The VREF pin should be connected to 10µF for ADC reference voltage and 10µF for PIR sensor.
Power-on Reset Characteristics
Ta=25˚C
Symbol Parameter Test Conditions Min. Typ. Max. Unit
VDD Conditions
VPOR VDD Start Voltage to Ensure Power-on Reset — — — — 100 mV
RRVDD VDD raising rate to Ensure Power-on Reset — — 0.035 — — V/ms
tPOR
Minimum Time for VDD Stays at VPOR to Ensure
Power-on Reset — — 1 — — ms
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Rev. 1.40 18 March 29, 2019 Rev. 1.40 19 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
System Architecture
A key factor in the high-performance features of the Holtek range of microcontrollers is attributed to
the internal system architecture. The devices take advantage of the usual features found within RISC
microcontrollers providing increased speed of operation and enhanced performance. The pipelining
scheme is implemented in such a way that instruction fetching and instruction execution are
overlapped, hence instructions are effectively executed in one cycle, with the exception of branch
or call instructions. An 8-bit wide ALU is used in practically all operations of the instruction set. It
carries out arithmetic operations, logic operations, rotation, increment, decrement, branch decisions,
etc. The internal data path is simplified by moving data through the Accumulator and the ALU.
Certain internal registers are implemented in the Data Memory and can be directly or indirectly
addressed. The simple addressing methods of these registers along with additional architectural
features ensure that a minimum of external components is required to provide a functional I/O and
A/D control system with maximum reliability and exibility. This makes the devices suitable for
low-cost, high-volume production for controller applications.
Clocking and Pipelining
The main system clock, derived from either a Crystal/ Resonator or RC oscillator is subdivided into
four internally generated non-overlapping clocks, T1~T4. The Program Counter is incremented at
the beginning of the T1 clock during which time a new instruction is fetched. The remaining T2~T4
clocks carry out the decoding and execution functions. In this way, one T1~T4 clock cycle forms
one instruction cycle. Although the fetching and execution of instructions takes place in consecutive
instruction cycles, the pipelining structure of the microcontroller ensures that instructions are
effectively executed in one instruction cycle. The exception to this are instructions where the
contents of the Program Counter are changed, such as subroutine calls or jumps, in which case the
instruction will take one more instruction cycle to execute.
  
     
      
  
  
  
    
 

  
 
 
 
  
System Clocking and Pipelining

Rev. 1.40 20 March 29, 2019 Rev. 1.40 21 March 29, 2019
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
HT45F23A/HT45F24A
TinyPowerTM Flash MCU with OPA & Comparators
For instructions involving branches, such as jump or call instructions, two instruction cycles are
required to complete instruction execution. An extra cycle is required as the program takes one
cycle to rst obtain the actual jump or call address and then another cycle to actually execute the
branch. The requirement for this extra cycle should be taken into account by programmers in timing
sensitive applications.
   
  
 






 
  
 
 



 
  
    
  
Instruction Fetching
Program Counter
During program execution, the Program Counter is used to keep track of the address of the
next instruction to be executed. It is automatically incremented by one each time an instruction
is executed except for instructions, such as “JMP” or “CALL” that demand a jump to a non-
consecutive Program Memory address. Note that the Program Counter width varies with the
Program Memory capacity depending upon which device is selected. However, it must be noted that
only the lower 8 bits, known as the Program Counter Low Register, are directly addressable by the
application program.
When executing instructions requiring jumps to non-consecutive addresses such as a jump
instruction, a subroutine call, interrupt or reset, etc., the microcontroller manages program control
by loading the required address into the Program Counter. For conditional skip instructions, once
the condition has been met, the next instruction, which has already been fetched during the present
instruction execution, is discarded and a dummy cycle takes its place while the correct instruction is
obtained.
Program Counter
Device Program Counter High Byte PCL Register
HT45F23A PC10~PC8 PCL7~PCL0
HT45F24A PC11~PC8 PCL7~PCL0
The lower byte of the Program Counter, known as the Program Counter Low register or PCL, is
available for program control and is a readable and writeable register. By transferring data directly
into this register, a short program jump can be executed directly. However, as only this low byte
is available for manipulation, the jumps are limited to the present page of memory that is 256
locations. When such program jumps are executed, it should also be noted that a dummy cycle will
be inserted.
The lower byte of the Program Counter is fully accessible under program control. Manipulating the
PCL might cause program branching, so an extra cycle is needed to pre-fetch. Further information
on the PCL register can be found in the Special Function Register section.