NXP Semiconductors PCAL6524EV-ARD User manual

UM11711
PCAL6524EV-ARD evaluation board
Rev. 1.0 — 19 January 2022 User manual
Document information
Information Content
Keywords PCAL6524, I2C-bus, 24-bit I/O bus, Arduino port, EVK
Abstract The PCAL6524EV-ARD evaluation board is a daughter card equipped with
Arduino port, designated for easy test and design of PCAL6524 IC, 24-bit port
expander, controlled through FM+ I2C 2-wire bus, with RESET. The board
is fully compliant with IMXRT1050 EVK, LPCXpresso55S69 (LPC55S69-
EVK) and i.MX 8M Mini LPDDR4 EVK (8MMINILPD4-EVK, 8MMINID4-EVK),
including GUI software control. The board can be attached to any device
equipped with Arduino port.

NXP Semiconductors UM11711
PCAL6524EV-ARD evaluation board
Rev Date Description
v.1.0 20220119 Initial version
Revision history
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IMPORTANT NOTICE
For engineering development or evaluation purposes only
NXP provides the product under the following conditions:
This evaluation kit is for use of ENGINEERING DEVELOPMENT OR
EVALUATION PURPOSES ONLY. It is provided as a sample IC pre-
soldered to a printed-circuit board to make it easier to access inputs,
outputs and supply terminals. This evaluation board may be used with any
development system or other source of I/O signals by connecting it to the
host MCU computer board via off-the-shelf cables. This evaluation board
is not a Reference Design and is not intended to represent a final design
recommendation for any particular application. Final device in an application
heavily depends on proper printed-circuit board layout and heat sinking
design as well as attention to supply filtering, transient suppression, and I/O
signal quality.
The product provided may not be complete in terms of required design,
marketing, and or manufacturing related protective considerations, including
product safety measures typically found in the end device incorporating the
product. Due to the open construction of the product, it is the responsibility of
the user to take all appropriate precautions for electric discharge. In order to
minimize risks associated with the customers’ applications, adequate design
and operating safeguards must be provided by the customer to minimize
inherent or procedural hazards. For any safety concerns, contact NXP sales
and technical support services.
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1 Introduction
This document describes the PCAL6524EV-ARD evaluation board. The evaluation board
is built around the PCAL6524, ultra-low voltage translating 24-bit I2C-bus/SMBus I/O
expander with interrupt output, reset, and configuration registers, produced by NXP
Semiconductors. The evaluation board serves as a daughter card that can be connected
through an Arduino port to various Arduino compatible (including original Arduino Uno
R3) EVK / mother boards for testing and measuring the characteristics of the PCAL6524
Device Under Test (DUT).
The PCAL6524EV-ARD daughter card communicates through the Arduino port with the
host device via the Fast-mode I2C-bus. Alongside the I2C-bus, three additional digital
lines allows the motherboard to control the DUT through the same Arduino port.
Power is delivered from the motherboard (EVK) through the Arduino port also.
The I/O pins of the DUT are organized in three ports. Each port (P0, P1 and P2) is 8-
bit wide, so the PCAL6524 manages a total amount of 24 I/O lines. The port P0 and P1
controls an on-board four-digit LED display through the MAX V CPLD (Intel/Altera). The
board contains also four on-board LEDs and four switches, connected to P2 port of the
DUT. All I/O lines are shared with two connectors for external access to the I/O pins (J6
and J7, see the schematic diagram of the PCAL6524EV-ARD evaluation board).
Additionally, a Graphical User Interface (Windows platform) is provided to facilitate the
evaluation of the daughterboard. The GUI is used with the following NXP evaluation
boards: IMXRT1050 EVK Board, LPCXpresso55S69 Development Board and i.MX 8M
Mini LPDDR4 EVK Board.
2 Finding kit resources and information on the NXP web site
NXP Semiconductors provides online resources for evaluation board and its supported
device(s) on http://www.nxp.com.
The information page for PCAL6524EV-ARD evaluation board is at http://http://
www.nxp.com/PCAL6524EV-ARD. The information page provides overview information,
documentation, software and tools, parametrics, ordering information and a Getting
Started tab. The Getting Started tab provides quick-reference information applicable
to using the PCAL6524EV-ARD evaluation board, including the downloadable assets
referenced in this document.
2.1 Collaborate in the NXP community
The NXP community is for sharing ideas and tips, ask and answer technical questions,
and receive input on just about any embedded design topic.
The NXP community is at http://community.nxp.com.
3 Getting ready
Working with the PCAL6524EV-ARD requires the kit contents, additional hardware, and a
Windows PC workstation with installed software.
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3.1 Kit contents
•Assembled and tested evaluation board in an antistatic bag
•Quick Start Guide
3.2 Assumptions
Familiarity with the I2C-bus is helpful but not required.
3.3 Static handling requirements
CAUTION
This device is sensitive to ElectroStatic Discharge (ESD). Therefore care
should be taken during transport and handling. You must use a ground strap
or touch the PC case or other grounded source before unpacking or handling
the hardware.
3.4 Minimum system requirements
This evaluation board requires a Windows PC workstation. Meeting these minimum
specifications should produce great results when working with this evaluation board.
•Computer with Windows 10
•One USB port (either 3.0 or 2.0 or 1.1 compatible)
•One of three EVK boards (MIMXRT1050-EVK, LPC55S69-EVK, 8MMINILPD4-EVK)
along with the associated firmware / GUI software
•USB cable for power and data connection between PC and EVK board (if not included
in the EVK package)
4 Getting to know the hardware
4.1 PCAL6524EV-ARD features
•I/O connectors for external access to IC input-output pins
•Four user switches connected to I/O pins of the IC
•Four user LEDs connected to I/O pins of the IC
•On-board LED display controlled from the I/O pins of the IC
•Equipped with Arduino Uno R3 port for direct connection with Arduino devices
•Fully compliant with IMXRT1050 EVK board, including GUI (Windows 10)
•Fully compliant with LPCXpresso55S69 dev. board, including GUI (Windows 10)
•Compliant with i.MX Mini LPDDR4 EVK board, including GUI (Windows 10)
Note: For i.MX Mini LPDDR4 EVK Board is necessary to use IMX8MMINI-IARD
interposer board between the EVK and PCAL6524EV-ARD daughterboard (see
IMX8MMINI-IARD User Manual).
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4.2 Kit featured components
Figure 1 identifies the main components on the board. The main elements are called out
in the picture. The Arduino port connectors (J1, J2, J3, J4) are located on the bottom side
of the board.
Figure 1. PCAL6524EV-ARD board, top view (up) and bottom view (down)
4.3 Block diagram
Figure 2 shows a block diagram of the PCAL6524EV-ARD daughterboard. Alongside the
DUT (U1), the board includes a series of peripherals that assures the operation of the
board. U1 is linked to Arduino interface (J1 to J4) through two busses: the I2C-bus and
the control bus.
The port P0 and P1 (8-bit wide each) controls the four-digit LED display (D9 to D12)
located on the board, through the MAX V CPLD which acts as display decoder/driver. Al
sixteen I/O lines are shared with the 16 BIT I/O PORT (J6).
The port P2 (8-bit wide) is shared with the on-board user LEDs D5 to D8, user switches
SW1 to SW4, and the 8 BIT I/O PORT (J7). The first four LSB I/O lines of the port P2
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drives the user LEDs, while the last four MSB lines are configured as inputs and are
controlled by the user switches.
The board contains two LDO voltage regulators, for 3.3 V (U3) and 1.8 V (U4), power
rails.
Figure 2. PCAL6524EV-ARD block diagram
4.4 Schematic diagram
The schematic diagram of PCAL6524EV-ARD is available at URL: http://www.nxp.com/
PCAL6524EV-ARD.
4.5 Arduino port
J1, J2, J3, and J4 are the mated pin headers of Arduino Uno R3 connectors, with the
same electrical function and placed on the board, so that the daughterboard can be
directly inserted in the Arduino port. The daughter card uses only five signal lines.
Table 1 details the pin chart of connectors, and the lines used in the circuit (see also the
SPF-46658.pdf schematic file).
Ref Des # Arduino label PCAL6524EV-ARD function
J1 (Power) 1 NC Not used
Table 1. The pin chart of Arduino connectors and their usage
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Ref Des # Arduino label PCAL6524EV-ARD function
2 IOREF Not used
3 RESET Not used
4 3.3V Not used
5 5V Power supply
6 GND Power supply return
7 GND Power supply return
8 Vin Not used
1 A0 Not used
2 A1 Not used
3 A2 Not used
4 A3 Not used
5 A4 / SDA I2C – SDA
J2 (analog, digital, I2C)
6 A5 / SCL I2C – SCL
1 D0 / RX Not used
2 D1 / TX Not used
3 D2 MAX_CLR
4 D3 / PWM MAX_OE
5 D4 MAX_CTRL_2
6 D5 / PWM MAX_CTRL_1
7 D6 / PWM MAX_CTRL_0
J4 (digital, UART, PWM)
8 D7 MAX_CLK
1 D8 RESET (control bus)
2 D9 / PWM ADDR (control bus)
3 D10 / SS / PWM INT (control bus)
4 D11 / MOSI / PWM Not used
5 D12 / MISO Not used
6 D13 / SCK Not used
7 GND Power supply return
8 AREF Not used
9 A4 / SDA Not used
J3 (mixed)
10 A5 / SCL Not used
Table 1. The pin chart of Arduino connectors and their usage...continued
The circuit is supplied with 5V from Arduino port through J1 and J3. Pin no. 5 of J1 is 5V
power supply, while pin no. 6, 7 of J1, and pin no. 7 of J3 represents the power supply
return (ground).
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4.6 I2C-bus
The PCAL6524EV-ARD board communicates with the host through an I2C-bus (pin
A3 – SCL, pin A2 – SDA). The communication provides internal configuration of the I/
O expander, reads the logic levels of the I/O pins configured as inputs, and sets the
logic level on the I/O pins configured as outputs. The internal configuration of the DUT
includes: direction of the digital I/O lines (input or output), polarity inversion, pull-up /
pull-down resistor enable, output strength, output configuration (push-pull or open-
drain), input latch configuration, interrupt register. The transaction speed of the I2C-bus
is compliant with Standard-mode (100kHz), Fast-mode (400kHz), and Fast-mode plus
(1MHz). For more details about I2C description and bus transactions, see PCAL6524
datasheet (NXP Semiconductors). The pull-up resistors of the I2C-bus are R43 and R44
(see SPF-46658.pdf schematic file).
4.7 Control bus
The control bus manages RESET, ADDR, and INT pins of the PCAL6524 IC. The
RESET pin is digital input and is controlled by the system host. Its role is to reset the I/
O expander when a time-out or other improper operation occurs. Asserting a low level of
this line forces a reset operation of the internal control section of the IC (puts the internal
registers in their default state and force a re-initialization of the I2C state machine, in
the same manner as power-on sequence). The RESET pin is controlled by the EVK
motherboard through J3-1 (ARDUINO port).
The ADDR pin is digital input and represents a programmable hardware address
package which can be asserted low or high, to assign two different slave addresses. The
input is controlled by the EVK through J3-2 (Arduino port).
The INT pin is an open-drain interrupt output, activated when any input state differs from
its corresponding input port register state, indicating to the host system that an input
state has changed. The line is monitored by the EVK through J3-3 ARDUINO port and
locally by the LED (D4) located on the daughterboard. The LED D4 can be deactivated
by removing JP1 jumper. When D4 is inactive (JP1 removed) the open-drain is polarized
through R42. R42 also has the role to compensate the voltage drop of D4 assuring 3.3V
high level in high state of the interrupt line (see SPF-46658.pdf schematic file).
4.8 I/O bus
The PCAL6524 IC contains 24 configurable I/O pins, organized in three ports, P0, P1,
and P2. All three ports are 8-bit wide. P0 and P1 are allocated to the four-digit LED
display (through MAX V CPLD, U2). The on-board LEDs (D5 to D8) and user switches
SW1 to SW4 are connected to port P2. All I/O lines of the PCAL6524 IC are linked to
the I/O port connectors for external access of the I/O lines (see the schematic file of the
PCAL6524EV-ARD daughterboard). Table 2 shows the allocation of the PCAL6524 I/O
lines (U1).
PCAL6524
(U1) pin Direction CPLD (U2) pin LED Switch 16 BIT – I/O PORT (J6) 8 BIT – I/O PORT (J7)
P0_0 I/O IO_9 - - 3 -
P0_1 I/O IO_10 - - 4 -
P0_2 I/O IO_11 - - 5 -
Table 2. I/O allocation
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PCAL6524
(U1) pin Direction CPLD (U2) pin LED Switch 16 BIT – I/O PORT (J6) 8 BIT – I/O PORT (J7)
P0_3 I/O IO_12 - - 6 -
P0_4 I/O IO_13 - - 7 -
P0_5 I/O IO_14 - - 8 -
P0_6 I/O IO_15 - - 9 -
P0_7 I/O IO_16 - - 10 -
P1_0 I/O IO_17 - - 11 -
P1_1 I/O IO_18 - - 12 -
P1_2 I/O IO_19 - - 13 -
P1_3 I/O IO_22 - - 14 -
P1_4 I/O IO_23 - - 15 -
P1_5 I/O IO_24 - - 16 -
P1_6 I/O IO_25 - - 17 -
P1_7 I/O IO_26 - - 18 -
P2_0 Output - D5 - - 2
P2_1 Output - D6 - - 3
P2_2 Output - D7 - - 4
P2_3 Output - D8 - - 5
P2_4 Output - - SW1 - 6
P2_5 Output - - SW2 - 7
P2_6 Output - - SW3 - 8
P2_7 Output - - SW4 - 9
Table 2. I/O allocation...continued
The on- board LEDs can be disabled by placing JP2 jumper in 2-3 position (OPTION
1, see SPF-46658.pdf file). This feature is useful when the user uses the board with
external device connected to J7 I/O port. The switches are connected to the bus through
620-ohm series resistors (R49 – R52), to avoid bus conflict (short-circuit if the line is set
accidentally as output and the switch is pressed).
4.9 CPLD
The PCAL6524EV-ARD board contains a MAX V series CPLD from Intel/Altera (U2,
5M80ZE64C5N). The role of this IC is decoder / driver for the on-board four-digit LED
display (D9 to D12). The CPLD works as signal bridge between the ports P0 and P1
of the PCAL6524 IC and the LED displays. Additionally, a six-line control bus is linked
between the MAX V IC and the Arduino port. For details, see SPF-46658.pdf schematic
file of PCAL6524EV-ARD daughterboard. The internal firmware of the MAX V CPLD is
controlled from the GUI application through the control bus. The CPLD control bus sets
the operation modes of MAX V CPLD. The MAX_CLK line is not used (IO_5/CLK0 pin of
U2 is masked). Table 3 details the operation modes and the corresponding logic states of
CPLD control bus.
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Bus line Direct Write Count Idle
MAX_CLK Not used Not used Not used
MAX_CLR 0 0 1
MAX_OE 0 1 0
MAX_CTRL_0 X [1] Controls the speed
of counting [2] X [1]
MAX_CTRL_1 Controls the indication
of digit 4 (D9). [3] Controls the direction of counting [2] 0
MAX_CTRL_2 X [1] Controls the counting status [2] X [1]
Table 3. CPLD control bus
[1] Don’t care
[2] See Section 4.9.2 and Table 4
[3] See Section 4.9.1
4.9.1 Direct write
When this mode is activated, the user can write decimal values from the GUI directly
to the on-board LED display on the PCAL6524EV-ARD board. For the Digit 1, 2, and 3
(D10, D11, and D12), the user can write decimal numbers from 0 to 9. For Digit 4 (D9),
the user can set the letter “U” or “d” (the initials of “Up” and “down”). Note that the digit
4 indication is controlled by the MAX_CTRL_1 control line (not through the one of I/O
line of the PCAL6524 IC). The dots of the digits can be set separately. See Table 4 and
Figure 3 for details.
PCAL6534 pin Direct write Count Idle
P0_0
P0_1
P0_2
P0_3
Write decimal numbers from the GUI to
Digit 1 (D12). The PCAL6524 pins are
configured as outputs.
Read the current data from
Digit 1 (D12). The PCAL6524
pins are configured as inputs.
P0_4
P0_5
P0_6
P0_7
Write decimal numbers from the GUI to
Digit 2 (D11). The PCAL6524 pins are
configured as outputs.
Read the current data from
Digit 2 (D11). The PCAL6524
pins are configured as inputs.
P1_0
P1_1
P1_2
P1_3
Write decimal numbers from the GUI to
Digit 3 (D10). The PCAL6524 pins are
configured as outputs. Read the current data from
Digit 3 (D10). The PCAL6524
pins are configured as inputs.
P1_4 Set ON/OFF the dot of Digit 1 (D12)
P1_5 Set ON/OFF the dot of Digit 2 (D11)
P1_6 Set ON/OFF the dot of Digit 3 (D10)
P1_7 Set ON/OFF the dot of Digit 4 (D9)
The PCAL6524 pins are
configured as inputs. The
lines are set in high state in
MAX V.
No action. The MAX V
corresponding pins are in high
Z.
Table 4. MAX V data bus
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4.9.2 Count mode
In this mode, an internal counter clocked by the RC oscillator of MAX V counts up and
down, at low speed (clock frequency: 7.6 Hz), or high speed (clock frequency: 61 Hz).
The counting status, direction, and speed are set by the MAX_CTRL_# lines of the
control bus. See Table 5 for MAX_CTRL lines. The current value of the counter is send
to ports P0 and P1 of the DUT IC (configured as inputs) and displayed in the GUI. The
range of the counter value is from 000 to 999.
Bus line Function State Description
0 Low speed (7.5 Hz)
MAX_CTRL_0 Speed 1 High speed (60 Hz)
0 down
MAX_CTRL_1 Direction 1 up
0 Counter is ON
MAX_CTRL_2 Status 1 Counter is OFF (the counting is stopped)
Table 5. MAX_CTRL_# control lines in Count mode
4.9.3 Idle mode
In this mode, the internal counter is stopped, the LED display is OFF, except the Digit 4
(D9) which is displaying “-“ (minus) sign (see Figure 3).
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Count mode - counting up
Count mode - counting down
Idle mode
Figure 3. PCAL6524EV-ARD on-board LED display
4.10 Jumpers and test points
The board contains two jumpers and several test points. Table 6 and Figure 4 detail
the jumper locations and their default configurations. Table 7 describes the test points
located on the PCAL6524EV-ARD board.
Ref Des Label Default Description
JP1 INT MONITOR - ON / OFF OFF OFF: Disable the interrupt monitor LED (D4)
Table 6. PCAL6524EV-ARD jumpers
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Ref Des Label Default Description
ON: Enable the interrupt monitor LED (D4)
1-2: Enable the user LEDs (D5 – D8)
JP2 USER LED – ON / OFF 1-2 2-3: Disable the user LEDs (D5 – D8)
Table 6. PCAL6524EV-ARD jumpers...continued
Figure 4. PCAL6524EV-ARD jumper locations
Ref Des Test point / jumper label Description
TP1 5V 5 V power rail
TP2 3.3V 3.3 V power rail
TP3 1.8V 1.8 V power rail
TP4 GND Ground
TP5 GND Ground
TP6 RST RESET input of PCAL6524 IC
TP7 SDA SDA line (I2C-bus)
TP8 SCL SCL line (I2C-bus)
TP9 ADDR ADDR input of PCAL6524 IC
Table 7. PCAL6524EV-ARD test points
5 Installing and configuring software tools
PCAL6524EV_ARD evaluation board is designed and built as a daughterboard able to
work in conjunction with a motherboard equipped with an Arduino port. The board was
built to be fully compatible with the following NXP Evaluation (EVK) boards:
•IMXRT1050 EVK Board;
•LPCXpresso55S69 Development Board;
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•i.MX 8M Mini LPDDR4 EVK Board;
Each mentioned above evaluation / development board benefits by firmware support
which can be downloaded from NXP company site (www.nxp.com/). Before starting,
the EVK motherboard must be programmed with the corresponding firmware package.
Additionally, a GUI application (Windows 10) is available for download from the NXP
site, allowing rapid testing and operation of PCAL6524EV-ARD daughterboard through
the one of above mentioned EVK. The GUI application is common for all three EVKs
and for the PCAL6xxx I/O expander development card family, manufactured by NXP
(PCAL6408A, PCAL6416A, PCAL6524 and PCAL6534 ICs). For details regarding
installation of the EVK firmware and GUI host software on PC please download
EVK_Firmware_And_GUI_Install_Guide_For_Arduino_Boards.pdf instruction file from
NXP site (www.nxp.com/). Once the software is installed, the first step is to select the
correct combination EVK – PCAL6524EV-ARD daughter card, and then the board can be
controlled from the GUI interface. See Section 6 and Section 7 for more details regarding
the operation of PCAL6524EV-ARD from GUI software.
6 Configuring the hardware
6.1 Using the PCAL6524EV-ARD with an IMXRT1050 EVK board
Figure 5 shows the required hardware for operation of the PCAL6524EV-ARD
daughterboard with IMXRT1050 EVK. The following items are necessary:
•One IMXRT1050-EVK board
•One PCAL6524EV-ARD daughterboard
•One USB-A / USB Micro-B cable
•A PC with Windows 10 operating system
The IMXRT1050 EVK motherboard can be powered by one of the three methods:
•Connecting an external 5VDC power supply to the barrel power connector (J2) on the
board
•Connecting a USB cable from the PC to the Micro-B USB connector (J9) on the board
•Connecting a USB cable from the PC to the USB connector (J28) on the board. When
the PC is connected in this fashion, the USB port can simultaneously act as a debug
interface. Therefore, by using a single USB cable connected to J28, the EVK can be
powered and at the same time linked to the PC for data exchange.
The older USB ports (from PC) are not able to deliver the necessary current (500mA),
before establishing the communication, use an external power supply (connected to J2).
From J1 on the EVK board (see Figure 5) the user can select the power configuration for
the motherboard. For further details, refer to the IMXRT1050 EVK Board Hardware User
Guide.
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Figure 5. PCAL6524EV-ARD daughterboard and IMXRT1050 EVK board, before starting
To configure the hardware and workstation, complete the following procedure:
1. Configure the suitable power configuration of EVK (J1). If using J28 for power supply,
the J1 jumper shall be placed in position 5-6. If using an external power supply
(connected to J2), the jumper J1 will be placed in position 1-2.
2. Insert the PCAL6524EV-ARD daughter card on the Arduino connector of the EVK
(see Figure 5).
3. Using USB connector J28, connect the EVK board to an USB port of the computer.
4. Install the IMXRT1050 target firmware (download from NXP site and see UM11581,
Arduino Arduino shields GUI and firmware installation manual for step-by-step
instructions).
5. Install GUI application (see UM11581, Arduino shields GUI and firmware installation
manual).
6. Open the GUI application to operate the device from the PC. For details regarding
GUI operation see Section 7.
Figure 6 shows the boards during the operation.
Figure 6. The assembly PCAL6524EV-ARD daughterboard / IMXRT1050 EVK board operation
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6.2 Using the PCAL6524EV-ARD with an LPCXpresso55S69 development
board
Figure 7 shows the required hardware for operation of the PCAL6524EV-ARD and
LPCXpresso55S69 EVK board. This configuration consists of:
•One LPCXpresso55S69 EVK board
•One PCAL6524EV-ARD daughterboard
•One USB-A / USB Micro-B cable
•A PC with Windows 10 operating system
The LPCXpresso55S69 development board is equipped with four USB Micro-B
connectors: P5, P6, P9 and P10. The board can be powered through any USB port.
Using P6 USB connector to connect the board to the PC simplifies the start-up operation
because P6 is designated for debugging and the USB cable thus accomplishes two tasks
at the same time: powering the board, and serving as a data link between the EVK board
and PC. For more details regarding power-up and operation of the LPCXpresso55S69
development board, see the LPCXpresso55S69/LPCXpresso55S28 Development Board
User Manual here.
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NXP Semiconductors UM11711
PCAL6524EV-ARD evaluation board
Figure 7. PCAL6524EV-ARD daughterboard and LPCXpresso55S69 motherboard, before starting
The following steps describe how to assemble, program, and operate the configuration
shown in Figure 7.
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NXP Semiconductors UM11711
PCAL6524EV-ARD evaluation board
1. Insert the PCAL6524EV-ARD daughter card to P16 – P19 connectors located
on LPCXpresso55S69 development board (see the marked pins of P16 – P19,
Figure 7);
2. Connect the development board using port P6 USB port of PC;
3. Install the LPCXpresso55S69 target firmware (download from NXP site and read the
EVK_Firmware_And_GUI_Install_Guide_For_Arduino_Boards.pdf instruction file);
4. Install GUI application on PC (see the instruction file called out in the previous step);
5. Open the GUI application to operate the device from the PC. For details regarding
GUI operation see Section 7.
Figure 8 shows the two boards in operation.
Figure 8. PCAL6524EV-ARD daughterboard/LPCXpresso55S69 motherboard operation
6.3 Using the PCAL6524EV-ARD with an i.MX 8M Mini LPDDR4 EVK
board
When an i.MX 8M Mini LPDDR4 EVK board is used with the PCAL6524EV-ARD board, a
third board (IMX8MMINI-IARD interposer board) must be used, especially designed and
built as EVK – daughterboard interconnection. The EVK board i.MX 8M Mini LPDDR4
is not equipped with an Arduino port; instead it has a 2 x 20 pin expansion connector
(J1003, see i.MX 8M Mini LPDDR4 EVK user manual). J1003 is a multipurpose port,
containing various digital I/O lines, including specialized I2C and SPI buses. Starting from
the expansion connector pin chart, an Arduino port interposer board was developed,
with the role of signal-to-signal bridge between the 2 x 20 connector pins on the i.MX
8M Mini LPDDR4 EVK and the mated connectors of the Arduino port present on the
PCAL6524EV-ARD daughterboard.
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PCAL6524EV-ARD evaluation board
To operate the setup, along with the EVK and the daughterboard, a third board must be
included in the setup assembly. Figure 9 shows the necessary boards and how these
boards are connected. The configuration consists of:
•One i.MX 8M Mini LPDDR4 EVK board
•One PCAL6524EV-ARD daughterboard
•One IMX8MMINI-IARD interposer board
•One USB-A / USB-C cable
•One USB-A / USB Micro-B cable
•A PC with Windows 10 operating system
It is recommended to attach the PCAL6524EV-ARD to the Arduino connectors of the
IMX8MMINI-IARD interposer board first, and then the resulting assembly to the i.MX 8M
Mini LPDDR4 EVK. This can be done by plugging J1 connector located on the interposer
board to J1003 connector on the EVK.
To power-up the EVK, an USB-C type cable connected to PORT 2 of the EVK is used.
The power switch SW101 on the EVK board must be set to ON position to power-up
the setup. Data communication is achieved by routing a separate USB (Micro-B type)
cable from an USB port on the PC to debug port (J901) on the EVK (see Figure 9 and
Figure 10).
The user may find details regarding power-up and operation of the setup assembly in
8MMINILPDDR4-EVK user manual and IMX8MMINI-IARD User Manual. The files can be
downloaded from www.nxp.com/.
Figure 9. The assembly PCAL6524EV-ARD daughterboard, IMX8MMINI-IARD interposer board, and i.MX 8M Mini
LPDDR4 EVK, before starting
To configure and operate the setup, follow the below steps:
1. Insert the PCAL6524EV-ARD onto the IMX8MMINI-IARD interposer board Arduino
connectors (located on the top side);
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