Texas Instruments C5535 DSPShield Quick user guide

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page i
C5535
DSP
SHIELD
Hardware Reference Manual
H/W Rev. A

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page ii
Revision History
Version Date Author Notes
0.1 Aug 12, 2013 D. Garcia 1
NOTES:
1. Initial release.
2.

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page iii
Table of Contents
1C5535 DSPShield ...................................................................................................... 1
1.1Key Features ...............................................................................................................1
1.2DSPShield Architecture..............................................................................................2
1.3User Control Elements ...............................................................................................3
1.4DSPShield Application Photos ...................................................................................4
2Power Management .................................................................................................. 4
2.1External Power Interface ............................................................................................4
2.2Internal Voltages ........................................................................................................6
2.3Voltage Monitoring ....................................................................................................6
2.4C5535 DSP Core Voltage ...........................................................................................7
3C5535 DSP and Internal Peripherals...................................................................... 7
3.1Parallel and Serial Peripherals ....................................................................................7
3.2Clock Sources .............................................................................................................8
3.3ROM Bootloader ........................................................................................................9
3.4/INT1, /INT0, XF, WAKEUP ..................................................................................10
3.5USB Controller .........................................................................................................10
3.6MMC/SDx Controller ...............................................................................................10
3.7I2C ............................................................................................................................10
4DSPShield Peripherals............................................................................................ 11
4.1I2C GPIO Expander .................................................................................................11
4.2OLED Display ..........................................................................................................14
4.3TLV320ACI3204 Audio Codec ...............................................................................14
4.4Micro SD Card Connector ........................................................................................14
4.5DIP Switch Inputs, LEDs and Push Button Reset ....................................................14
4.6DSP Expansion Connector .......................................................................................15
5Emulation................................................................................................................. 16
5.1FTDI FT2232H .........................................................................................................16
5.2Power via XDS-USB ................................................................................................17
6Arduino Interface.................................................................................................... 17
6.1Arduino/DSPShield Interface Block Diagram .........................................................19
6.1.1Interface Logic Levels ............................................................................... 19
6.1.2Analog Inputs ............................................................................................ 20
6.2Arduino/DSPShield Reset Multiplexing ..................................................................20

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page iv
6.2.1Default Configuration ................................................................................ 22
6.2.2C5535 Isolated from ARD_RESETN pin ................................................. 23
6.2.3C5535 Resets Arduino ............................................................................... 23
6.2.4C5535 Self Resets ...................................................................................... 23
6.2.5Emulator Only Resets the DSPShield ....................................................... 23
6.3DSPShield UART Multiplexing ...............................................................................23
6.3.1DSP Expansion Connector ........................................................................ 25
6.3.2Arduino IO[1:0] ......................................................................................... 25
6.3.3Emulator Serial Port .................................................................................. 25
6.4Arduino/DSPShield I2C Interface ............................................................................26
6.5Arduino SPI Interface ...............................................................................................26
6.5.1Arduino Master/C5535 DSP Isolated ........................................................ 27
6.5.2Arduino Slave/C5535 DSP Master ............................................................ 28
6.5.3Arduino Isolated/C5535 DSP Master ........................................................ 28
7Resistor Multiplexing Configurations................................................................... 28
8Stand-Alone Mode .................................................................................................. 30
9Assembly Drawings and Schematics ..................................................................... 31

Reference documents
Title / source Owner Version
1 TMS320C5535 Data Sheet
SPRS737B AUGUST 2011–REVISED MARCH 2012 TI
2 TMX320C5535 Technical Reference Manual
SPRUH87C August 2011–Revised March 2012 TI
3 TLV320AIC3204 Ultra Low Power Stereo Audio Codec
SLOS602B –SEPTEMBER 2008–REVISED OCTOBER 2012 TI
4 TCA6416A I2C to GPIO Expander
SCPS194A – MAY 2009– REVISED NOVEMBER 2009 TI
5 Dual High Speed USB to Multipurpose UART/FIFO IC
http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT2232H.pdf FTDI
6 Arduino UNO Information
http://arduino.cc/en/Main/ArduinoBoardUno Arduino
7 OLED Display OSD9616P0992-10
http://osddisplays.com/
OSD
Display

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page v
Acronyms Abbreviations and Definitions
Arduino Family of Open Hardware uC Boards
Arduino UNO 2chip Arduino uC Board
Arduino Leonardo 1chip Arduino uC Board
CCS Code Composer Studio TI Emulation Software
DC-DC Switching regulator
DSP Digital Signal Processor
DNI Do Not Install
Energia Open Source software IDE for TI Processors
GPIO General Purpose Input Output
I2C Inter-Integrated Circuit (2-pin serial bus)
I2S Integrated Interchip Sound (4-pin serial bus for audio devices)
IDE Integrated Development Environment
LCD Liquid Crystal Display
LDO Low Drop-Out regulator
MMC/SD Multimedia Card/Secure Digital (flash memory)
OLED Organic Light Emitting Diode (Display)
UART Universal Asynchronous Receiver Transmitter (serial bus)
XDS Extended Development System. JTAG Emulators for TI
Processors (embedded or external)

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 1
1 C5535 DSPShield
The C5535 DSPShield is an evaluation board for the Texas Instruments TMS320C5535
Fixed-Point Digital Signal Processor (DSP). It is designed to be both a “Shield” (i.e.
daughter card) for the Arduino Open-Hardware family of microcontroller (uC) boards
and also a stand-alone development board. With a rich set of hardware features and a
connector for prototyping expansion, the C5535 DSPShield can be used to develop
applications such as
• Wireless Audio Devices (e.g., Headsets, Microphones, Speakerphones)
• Echo Cancellation Headphones
• Portable Medical Devices
• Voice Applications
• Industrial Controls
• Fingerprint Biometrics
• Software-defined Radio
1.1 Key Features
The key features of the C5535 DSPShield are shown in Figure 1. The features include:
TI TMS320C5535AZHHA10 (100MHz) Digital Signal Processor
TI TLV320AIC3204IRGBR Stereo Audio Codec with separate stereo in and
stereo out connectors
Micro SD Card Connector
USB 2.0 interface to the C5535 DSP
OLED 96x16 pixel display
Arduino Compatible Header Connectors
Arduino Interface is compatible with Energia software IDE and API
Embedded USB XDS100-V2 JTAG emulator with secondary serial port
oJTAG is compatible with TI Code Composer Studio software IDE
oSecondary serial port is compatible with Energia software IDE and API
40-pin DSP Expansion Connector
3 user controlled LEDs,
4 user readable DIP switches
1 hardware reset push button switch
Flexible Power Sourcing

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 2
Figure 1. Key Features of the C5535 DSPShield
1.2 DSPShield Architecture
The C5535 DSP is a peripheral rich processor. However, to limit the pin count, the
C5535’s pins are heavily multiplexed. Depending on the application, the C5535 is
programmed with the appropriate internal peripherals routed to its external pins. The
DSPShield maintains this flexibility by using additional discrete multiplexers to connect
the C5535’s GPIO/peripheral pins to the appropriate points on the board. Additonal
flexibility can also be found in the power management for the board and in the
Arduino/DSPShield interface. The DSPShield block diagram is shown in Figure 2.
The DSPShield architecture consists of the following major blocks:
1. Power Management
2. The C5535 DSP and Internal Peripherals
3. DSPShield Peripherals
4. Arduino Interface
5. DSP Expansion Connector
6. XDS100-V2 Embedded Emulator

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C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 4
P10 Arduino ICSP Male/Female Header 6.1
J1 Alternate JTAG Header when Embedded Emulator N/A 5.1
J2 Audio Codec MIC input 4.3
J3 Audio Codec Headphone output 4.3
JPA DSP-USB and/or XDS-USB +5V Input Select Jumper 2.1
JPB Arduino +5V Input/Output Select Jumper 2.1
JPC Arduino +3.3V Output ONLY Select Jumper 2.1
JPD Arduino IOREF Input/Output Select Jumper 6.1.1
JPE Internally generated Ardino IOREF +5V or +3.3V Select Jumper 6.1.1
JPF XDS-USB +5V Connector Select Jumper 5.2
LED-XF C5535 XF Status 3.3, 4.5
LED0 General Purpose LED 4.5
LED1 General Purpose LED 4.5
LED2 General Purpose LED 4.5
XDS-LED Emulator Connected Status 5.1
Table 1. User Control Elements
1.4 DSPShield Application Photos
Inset photographs here.
DSPShield + Arduino UNO
DSPShield + Arduino UNO + Arduino Shield (suggestions?)
DSPShield + Arduino Leonardo using 2 USB cables
DSPShield + DSP Daughter Card (Audio Shield)
DSPShield + Arduino Shield + DSP Daughter Card
Other???
2 Power Management
The DSPShield requires a single +5V source. All other required voltages used on the
board are derived from this source.
2.1 External Power Interface
The +5V source can come from the DSP-USB connector (P1), XDS-USB connector (P9),
or from the Arduino Power Header (P7). The DSPShield power management block
diagram is shown in Figure 3. Jumpers JPA, JPB, JPC and JPF control the multiplexing
of power sources into and out of the board. Some common power management
configurations are listed in Table 2.
NOTES:
1. Schottky diodes allow both USB cables to be connected at the same time.
However, the inclusion of the diodes in the power path drops the nominal +5V to
about +4.3V due to the diode voltage drop.
2. The DSPShield does not use the +3.3V from the Arduino Power Header.
However, the DSPShield can source it.

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C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 6
2.2 Internal Voltages
There are a number of voltages that can be found on the DSPShield. They are derived
from various ICs and can be monitored at certain points. Table 3 lists the voltages, test
points and the devices/functions powered by the voltages.
Voltage Test Point Source Device/Functions
+5V TP8 External 1. LMR10510X DC-DC Regulator
2. ARD_INTF_VCC
3. ARD_5V (sourcing)
+3.3V TP9 LMR10510X DC-
DC Regulator (VR1)
1. C5535 USB_VDDOSC
2. C5535 USB_VDDA3P3
3. C5535 USB_VDDPLL
4. C5535 DVD_DRTC
5. C5535 LDOI
6. C5535 DVDDIO
7. All Muxes
8. SD Card
9. GPIO Expander 2
10. AIC3204 IOVDD
11. ARD_INTF_VCC
12. ARD_3.3V (sourcing)
13. DSP Expansion Header +3.3V
14. Emulator +3.3V
+1.8V TP5, TP6 Internal AIC3204
LDO
1. AIC3204 AVDD, TP5
2. AIC3204 DVDD, TP6
+1.3V TP10 LP3982 LDO (VR2) 1. C5535 CVDDRTC
2. C5535 CVDD (0 OHM resistor mux
selectable)
3. GPAIN CLAMP DIODES
+1.3V
(C5535)
Pin 1 of C19
Or TP3
C5535 DSP_LDOO 1. C5535 CVDD (0 OHM resistor mux
selectable. DEFAULT configuration)
+1.3V
(C5535)
Pin 1 of C45 C5535 USB_LDOO 1. C5535 USB_VDDA1P3
2. C5535 USB_VDD1P3
+1.3V
(C5535)
Pin 1 of C53 C5535 ANA_LDOO 1. C5535 VDDA_ANA
2. C5535 VDDA_PLL
+1.8V
(FT2232H)
Pin 1 of C125 FTDI FT2232H
VREGOUT
1. FT2232H VCORE
+7.3V Pint 1 of C70 Internal OLED DC-
DC regulator
1. OLED Display
GND TP11 - 1. Digital Ground
AGND0 TP7 - 1. AIC3204 Analog Ground
Table 3. DSPShield Voltages and Grounds
2.3 Voltage Monitoring
The output voltages of the LMR10510X DC-DC (+3.3V) regulator and the LP3982
(+1.3V) LDO regulator are monitored by a TPS386596L33 Quad Reset Supervisory IC.

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 7
If either voltage drops below certain thresholds, the TPS65001’s active low open-drain
reset output will go low and reset the C5535 DSP and the DSPShield.
2.4 C5535 DSP Core Voltage
The C5535 DSP’s +1.3V Core Voltage, CVDD, can be driven either by its internal LDO
or by the LP3982 LDO. The selection is accomplished by populating certain
combinations of resistors R25, R26, R27 and R28. The two options are listed in Table 5.
CVDD = C5535 DSP_LDOO
(DEFAULT )
R25 = DNI
R26 = 0 Ohm Resistor
R27 = 0 Ohm 1/8W Resistor
R28 = DNI
CVDD = LP3882 LDO R25 = 10.0K Ohm Resistor
R26 = DNI
R27 = DNI
R28 = 0.0 Ohm 1/8W Resistor
Table 4. C5535 DSP Core Voltage Selection
3 C5535 DSP and Internal Peripherals
The C5535 DSP is a high-performance, low-power, fixed-point Digital Signal Processor.
It has dual multipliers, dual ALUs, and a tightly coupled FFT hardware accelerator for
performing math intensive signal processing algorithms. It has a multiple I/O peripherals
that allow it to easily connect to serial Analog to Digital Converters, Digital to Analog
Converters and integrated codecs.
3.1 Parallel and Serial Peripherals
The C5535 DSP’s internal External Bus Selection Register (EBSR) determines which of
the following: LCD controller, I2S0, I2S1, I2S2, I2S3, UART, SPI, MMC/SD and GPIO
signals appear at the chip’s multiplexed GPIO pins. These peripherals can be grouped
into 3 groups as shown in Tables 5a, 5b and 5c. For each group, only one mode of
operation is available at a given time. Note that the DSPShield architecture further limits
the group mode selection.
PP MODE Multiplexed I/O Board Level limitations
Modes
0,2,3,4,5
- Not Supported
Mode 1 SPI/I2S2/UART/6 GPIO Fully Supported.
-I2S2 multiplexed between AIC3204 and DSP
Expansion Connector.
-UART multiplexed between Arduino, XDS
Serial Port and DSP Expansion connector.
-SPI multiplexed between Arduino and DSP

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 8
Expansion connector.
-GPIO[12:15] routed directly to DSP
Expansion connector.
-GPIO16 routed to the DSP Expansion
Connector IF R67 is Installed and R66 is Not
Installed (This is not the Default)
-GPIO17 routed to the DSP Expansion
Connector IF R69 is Installed and R68 is Not
Installed (This is not the Default)
Mode 6 SPI/I2S2/I2S3/6 GPIO Fully Supported.
-I2S2 multiplexed between AIC3204 and DSP
Expansion Connector.
-I2S3 routed to DSP Expansion Connector
when UART_MUX_SEL=0.
-SPI multiplexed between Arduino and DSP
Expansion connector.
-GPIO[12:15] routed directly to DSP
Expansion connector.
-GPIO16 routed to the DSP Expansion
Connector IF R67 is Installed and R66 is Not
Installed (This is not the Default)
-GPIO17 routed to the DSP Expansion
Connector IF R69 is Installed and R68 is Not
Installed (This is not the Default)
Table 5a. C5535 PPMODE
SP1
MODE
Multiplexed I/O Board Level limitations
Mode 0,1,2 SD1/I2S1/GPIO[6:11] Fully Supported.
-All signals are routed directly to the DSP
Expansion Connector.
Table 5b. C5535 SP1MODE
SP0
MODE
Multiplexed I/O Board Level limitations
Mode 0 SD0 SD0 signals are dedicated to the SD Card Connector
Modes 1, 2 - Not Supported
Table 5c. C5535 SP0MODE
3.2 Clock Sources
The C5535 DSP has 3 input clock sources: USB_MXI pin, CLKIN pin, and an internal
Real Time Clock (RTC). The USB_MXI input is connected to a 12 MHz oscillator and is
the clock source for all USB peripheral activity. The CLKIN input is also connected to a
12 MHz oscillator while the RTC is connected to a 32.768 KHz crystal. Either CLKIN or

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 9
the RTC can be the reference source for the C5535 DSP’s system clock generator.
Resistors R8, R9, R10 and R59 select the source as shown in Table 6. The different
clocks within the system clock generator block can be output on the C5535 DSP’s
CLKOUT pin and monitored at Test Point TP1.
System Clock Generator
Reference Source
Resistor Select
12MHz External Oscillator
(Default)
R8=DNI, R9=10K Ohm, R10=DNI, R59=0 Ohm
32.768 RTC R8=0 Ohm, R9=DNI, R10=0 Ohm, R59=DNI
Table 6. System Clock Generator Reference Source Select
3.3 ROM Bootloader
The C5535 DSP has an on-chip ROM Bootloader (RBL). It samples the following
interfaces, in order, looking for a boot signature: SPI EEPROM, I2C EEPROM,
MMC/SD0 AND UART/USB. Once a boot signature is detected, the C5535 DSP will
download the boot image and then jump to the entry point specified in the image. For the
DSPShield, the SD0 peripheral connected to the micro SD Card connector is the default
boot source. Figure 4 shows the Bootloader Software Architecture (from the C5535 DSP
datasheet). In the case where no boot source is found, the LED_XF will remain lit.
Figure 4. Bootloader Software Architecture

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C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 11
devices on the I2C bus on the DSPShield are listed in Table 7 along with their 7-bit
address.
I2C Peripheral I2C Address
GPIO Expander 1 0x20
GPIO Expander 2 0x21
OLED Display 0x3C
AIC3204 Codec 0x18
DSP Expansion Connector I2C Extension, +3.3V Logic Levels
Arduino Digital Interface I2C Extension, Buffered at +5V Logic Levels
DSP_I2C_EN must be a logic ”1”
Table 7. Devices on the I2C Bus
The I2C bus is also extended to the Arduino and DSP Expansion Connectors. For the
DSP Expansion Connector, the bus remains at +3.3V levels and is not buffered. For the
Arduino connector, the I2C bus is buffered by a TI PCA9515B I2C Repeater IC. The IC
provides a translation between the Arduino’s +5V logic levels and the C5535 DSP’s
+3.3V logic levels. On power up and reset, the PCA9515B is disabled. This isolates the
DSPShield’s internal I2C bus during the boot sequence. After boot, the C5535 DSP can
enable the PCA9515B by setting DSP_I2C_EN on Port0.2 of GPIO Expander 2 to a “1”.
4 DSPShield Peripherals
In addition to the C5535 DSP’s internal peripherals, the DSPShield has several external
peripherals that increase its functionality. The peripherals are:
1. Two TCA6416A 16-bit I2C to GPIO Expander chips
2. OLED display
3. TLV320ACI3204 Stereo Audio Codec
4. Micro SD Card connector
5. DIP Switch Inputs, LEDs, and Push Button Reset
6. Additional peripherals can be added through the use of the 40-pin DSP Expansion
Connector and the Arduino Interface Connectors.
4.1 I2C GPIO Expander
The two TCA6416A (I2C to GPIO) Expander chips increase the number of GPIOs under
the C5535 DSP’s direct control. Each chip provides an additional 16 GPIOs. Tables 8a
and 8b list the direction (after programming) and function of each GPIO.
On power up and reset, all the GPIOs are initialized as inputs. Some GPIO pins have
external pull up or pull down resistors connected to them that allow the various
DSPShield external peripherals to power up in a known state. For example, the U3 4-bit
1to2 multiplexer’s select pin is connected to Expander 2’s Port0.4 GPIO and also to a

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 12
pull up resistor. On power up and reset the C5535 DSP’s I2S lines are multiplexed to the
codec.
To prevent glitches during initialization, the following sequence should be followed to
program output pins.
1. Program the Expander Output Port Registers to the default values listed in tables
8a and 8b.
2. Program the appropriate direction bit in the Expander Configuration Registers for
GPIOs that will be outputs.
3. After initialization, the Output Port Registers can be changed depending on the
application.
The GPIO Expanders also have an open drain active-low interrupt output. The interrupt
outputs of the two GPIO Expanders are wire-ORed together and connected to the C5535
DSP’s INT1N input. An interrupt is generated by any rising or falling edge of the port
inputs in the input mode. Resetting the interrupt is achieved when the data on the port is
changed to the original setting or when data is read from the port that generated the
interrupt. This interrupt feature of the GPIO Expander is very basic and lacks an interrupt
mask capability.
NOTES:
1. There are no external pull up or pull down resistors on GPIO pins that can be
programmed as input or output. If unconnected, these unused GPIO should be
programmed as an output to avoid floating inputs. The output value is irrelevant,
but a logic zero is preferred.
2. Expander 1 GPIOs can use +5V or +3.3V logic levels depending on the state of
JPD and JPE. Expander 2 GPIOs use +3.3V logic levels only.
Expander 1
I2CAddr=0x20
Programmed
Direction
Function
Reset value: all GPIO are Inputs
Port0.0 I/O Arduino I/O0
- If unconnected, set to output a logic 0
Port0.1 I/O Arduino I/O1
- If unconnected, set to output a logic 0
Port0.2 I/O Arduino I/O2
- If unconnected, set to output a logic 0
Port0.3 I/O Arduino I/O3
- If unconnected, set to output a logic 0
Port0.4 I/O Arduino I/O4
- If unconnected, set to output a logic 0
Port0.5 I/O Arduino I/O5
- If unconnected, set to output a logic 0
Port0.6 I/O Arduino I/O6
- If unconnected, set to output a logic 0
Port0.7 I/O Arduino I/O7

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 13
- If unconnected, set to output a logic 0
Port1.0 I/O Arduino I/O8
- If unconnected, set to output a logic 0
Port1.1 I/O Arduino I/O9
- If unconnected, set to output a logic 0
Port1.2 O
Pull Down
Resistor on Pin
UART_CNTRL0: Arduino UART Mux Control
Default = 0
Port1.3 O
Pull Up
Resistor on Pin
UART_CNTRL1: Arduino UART Mux Control
Default = 1
Port1.4 O
Pull Down
Resistor on Pin
UART_CNTRL2: Arduino UART Mux Control
Default = 0
Port1.5 O
Pull Up
Resistor on Pin
UART_CNTRL3: Arduino UART Mux Control
Default = 1
Port1.6 O
Pull Down
Resistor on Pin
RST_CNTRL0: Reset Mux Control
Default = 0
Port1.7 O
Pull Down
Resistor on Pin
RST_CNTRL1: Reset Mux Control
Default = 0
Table 8a. Expander 1 GPIO Definitions
Expander 2
I2CAddr=0x21
Programmed
Direction
Function
Reset value: all GPIO are Inputs
Port0.0 O LED0: 0=OFF, 1=ON
Port0.1 O LED1: 0=OFF, 1=ON
Port0.2 O
Pull Down
Resistor on Pin
DSP_I2C_EN
0= Disable, 1= Enable
Default = 0
Port0.3 O
Pull Down
Resistor on Pin
SPI_RX_SEL
0=SPI RX input from Arduino MISO
1=SPI RX input from DSP Expansion Header
NOTE: Manufacturing Default = 0. An alternative pull up
resistor pad is available on the board.
Port0.4 O
Pull Up
Resistor on Pin
I2S2_MUX_SEL
0=Connected to DSP Expansion Header
1=Connected to AIC3206 Codec
NOTE: Manufacturing Default = 1. An alternative pull down
resistor pad is available on the board.
Port0.5 O
Pull Up
Resistor on Pin
UART_MUX_SEL
0=Connected to DSP Expansion Header
1=C5535 DSP UART TX and RX connected to Arduino
UART multiplexing circuitry
NOTE: Manufacturing Default = 1. An alternative pull down
resistor pad is available on the board.

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 14
Port0.6 O LED2: 0=OFF, 1=ON
Port0.7 O
Pull Down
Resistor on Pin
DSP_SPI_EN
0=Arduino SPI TXB0104 Transceiver Disabled
1=Arduino SPI TXB0104 Transceiver Enabled
Default = 0
Port1.0 I/O DSP Expansion Header PIN6
- If unconnected, set to output a logic 0
Port1.1 I/O DSP Expansion Header PIN4
- If unconnected, set to output a logic 0
Port1.2 I/O DSP Expansion Header PIN5
- If unconnected, set to output a logic 0
Port1.3 I/O DSP Expansion Header PIN3
- If unconnected, set to output a logic 0
Port1.4 I State of switch 4 on DIP Switch SW1
Port1.5 I State of switch 3 on DIP Switch SW1
Port1.6 I State of switch 2 on DIP Switch SW1
Port1.7 I State of switch 1 on DIP Switch SW1
Table 8b. Expander 2 GPIO Definitions
4.2 OLED Display
The OLED Display provides a 96x16 pixel display. It is programmed via the C5535
DSP’s I2C bus and has an I2C address of 0x3C.
4.3 TLV320ACI3204 Audio Codec
The AIC3204 Audio Codec interfaces to the C5535 DSP via the I2C and I2S2 buses. The
C5535 DSP’s I2S2 Bus is routed to the AIC3204 when I2S2_MUX_SEL = 1. The
AIC3204’s I2C address is 0x18.
The microphone stereo input is routed to the Pink jack, J1. The head phone stereo output
is routed to the Green jack, J2.
4.4 Micro SD Card Connector
Interface SD0 is connected to a micro SD card connector, P2. The micro SD card is the
default boot source for the C5535 DSP’s on-chip ROM Bootloader (RBL).
4.5 DIP Switch Inputs, LEDs and Push Button Reset
The status of switches 1, 2, 3 and 4 of DIP switch SW1, can be read by the C5535 DSP
via Port1.7, 1.6, 1.5, 1.4 of the GPIO Expander 2, respectively. “ON” corresponds to a
logic “1” in the GPIO Expander Input Register.
Three general purpose status LEDs are available for display by the C5535 DSP. They are
controlled by the output value of Port0.0, 0.1, and 0.6 of GPIO Expander 2. They
correspond to LEDs labeled as LED0, LED1 and LED2 on the board. A separate LED is

C5535 DSPShield H/W Reference Manual Version 0.1
In Collaboration with Stanford University
page 15
tied to the C5535 DSP’s XF general purpose output pin. It is labeled LED-XF on the
board. Writing a logic “1” to the appropriate registers will turn on the LEDs.
A manual reset is provided by push button SW2. Pressing this switch will place the
DSPShield in its default state.
4.6 DSP Expansion Connector
The DSP Expansion Connector routes power, ground, and various C5535 DSP GPIOs
and signals to a 40-pin Female Receptacle, P2. The receptacle mates to standard 0.1”
pitch 0.025” square post male headers. The signals available on the DSP Expansion
Connector are listed in Table 9. All signals used 3.3V logic levels.
Pin Signal Name Direction Function
1 +5V O Power to Header
2 +3.3V O Power to Header
3 X_GPIO3V3_13 I/O GPIO (Expander2 Port1.3)
4 X_GPIO3V3_11 I/O GPIO (Expander2 Port1.1)
5 X_GPIO3V3_12 I/O GPIO (Expander2 Port1.2)
6 X_GPIO3V3_10 I/O GPIO (Expander2 Port1.0)
7 X_SCL O I2C SCL
8 X_LCD_D9_I2S2_FS_GP19_SPI_CS0 I/O C5535 PPMODE SIGNALS
9 X_SDA O I2C SDA
10 X_LCD_D8_I2S2_CLK_GP18_SPI_CLK I/O C5535 PPMODE SIGNALS
11 X_NMIN I/O C5535 INT0
12 X_LCD_D11_I2S2_DX_GP27_SPI_TX I/O C5535 PPMODE SIGNALS
13 X_RESETN I/O C5535 PPMODE SIGNALS
14 X_LCD_D10_I2S2_RX_GP20_SPI_RX I/O C5535 PPMODE SIGNALS
15 GND - GROUND
16 X_LCD_D2_GP12 I/O C5535 PPMODE SIGNALS
17 X_DSP_SPI_TX I/O C5535 PPMODE SIGNALS
18 X_LCD_D3_GP13 I/O C5535 PPMODE SIGNALS
19 X_SPI_RX I/O C5535 PPMODE SIGNALS
20 X_LCD_D4_GP14 I/O C5535 PPMODE SIGNALS
21 X_DSP_SPI_CS3 I/O C5535 PPMODE SIGNALS
22 X_LCD_D5_GP15 I/O C5535 PPMODE SIGNALS
23 X_DSP_SPI_CS2 I/O C5535 PPMODE SIGNALS
24 X_RTCCLK_GP16 I/O R66=IN, R67=DNI (DEFAULT)
DSP_RTC_CLKOUT
R66=DNI, R67=IN
X_LCD_D6_GP16
25 X_DSP_SPI_CS1 I/O C5535 PPMODE SIGNALS
26 X_12MHZ_GP17 I/O R68=IN, R69=DNI (DEFAULT)
DSP_EXP_12MHZ (OSC)
R68=DNI, R69=IN
X_LCD_D7_GP17