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AM335x Starter Kit Hardware User Guide


This document provides the design information on the AM335x processor based Starter Kit (TMDSSK3358) to users.


The AM335x Starter Kit (TMDSSK3358) can be used as an evaluation and development platform for low cost AM335x based solutions and networking platforms. The embedded emulation logic allows emulation and debug using standard development tools such as TI’s Code Composer Studio by just using the supplied USB cable. It is not intended for use in end products. All of the design information is freely available and can be used as the basis for the development of an AM335x based product.

EVM System View

TMDSSK3358 is partitioned into two different boards: the main board (processor, peripherals & the main power supply) and the LCD Carrier board (LCD and touch screen). The TMDSSK3358 main board and the LCD carrier board mounted are mounted together using 10mm standoffs. The TMDSSK3358 main board has dimensions of 5.257” x 2.798 “and that of the LCD Carrier board is 4.963” x 2.798 “. The Top and the Bottom side views of the TMDSSK3358 are shown in the pictures provided below.

Top view


Figure 1: TMDSSK3358 Top view

Bottom view


Figure 2: TMDSSK3358 V1.2B Bottom View

System view


Figure 3: TMDSSK3358 System View

Schematics/Design Files

Functional Block Diagram

This section describes about the major functional blocks of the TMDSSK3358. The Functional block diagram of the TMDSSK3358 design is shown below.


Figure 4: TMDSSK3358 Block Diagram


The AM3358ZCZ processor is the central processor for TMDSSK3358. All the resources on the board surround the AM3358 processor to provide development capabilities for hardware and software. See the AM3358 datasheet and TRM for the details about the processor.

There are system configuration signals, SYSBOOT, that can be set on the EVM to define some startup parameters on the AM335x processor. See the Configuration/Setup section later for more details.


The main clock for the processor is derived from a 24MHz crystal. An on-board oscillator in the AM3358 generates the base clock and subsequent module clocks as needed within the AM3358 processor. A 32kHz clock for the RTC on the AM3358 is derived from a 32kHz crystal on board.

Reset Signals

Power On Reset to the AM335x is driven by the PMIC. SYS_ WARMRESETn is a signal running to several peripherals and AM335x which performs a reset on those peripherals. SYS_WARMRESETn is asserted by a pushbutton on the main board and is used to force a reset of the AM335x. AM335x can also pull down on the RESET_INOUTn signal to cause the SYS_ WARMRESETn line to go active. The RTC_PORZ reset signal for the RTC section is derived using AND Gates.


The power input to TMDSSK3358 is from a 5V Power Supply. This 5V power is provided as power input to the Power Manager TPS65910A3. The power requirements of the processor are taken care of by the Power Manager IC TPS65910A3. The Power ON LED "D5" is ON if the PMIC output power VAUX33 is available ( to indicate the active status of the PMIC). The power sequencing requirements of the AM335X processor (see the AM335x datasheet) are handled automatically by the TPS65910A3 PMIC.

Note: When powering the TMDSSK3358 EVM, always use the recommended power supply (CUI/V-Infinity Part Number EMSA050300-P6P-SZ, Model 3A-182WP05) or equivalent model having output voltage of +5VDC and output current max 3.0 Amps. A power supply is not included with the kit.

Power Management IC

TMDSSK3358 uses the TPS65910A3 power management IC. The I2C0 on AM335x is used to control the TPS65910A PMIC.

The PWRON input of PMIC is connected to an external push-button. The built-in debouncing time defines a minimum button press duration that is required for button press detection. Any button press duration which is lower than this value is ignored, considered an accidental touch.

For AM335x, the following power supplies from the TPS65910A are used.

TPS65910 Power Supply/Other sources AM335x Power Rail Voltage
VAUX2 (300mA) VDDSHV6 (300mA) 3.3V
VMMC (300mA) VDDSHV2,3,4,5 (300 mA), VDDA3P3V_USB0/1 (10 mA) 3.3V
VDD2 SMPS (1500mA) VDD_CORE (1000mA) 1.1V
VDD1 SMPS (1500mA) VDD_MPU (1500mA) 1.2V
No supply needed VDD_RTC 1.1V
VRTC (External LDO) VDDS_RTC (10mA) 1.8V
VIO_SMPS (1000mA) VDDS_DDR (200mA) 1.5V
VIO_SMPS (1000mA) DDR_VREF (10mA) 0.9V
VDAC (150mA) VDDS (100mA) 1.8V
VDIG1 (300mA) VDDSHV1 1.8V


VDIG2 (300mA) VDDS_SRAM_MPU_BB (40mA) 1.8V
VDIG2 (300mA) VDDS_PLL_DDR (25mA) 1.8V
VDIG2 (300mA) VDDS_PLL_CORE_LCD (25mA) 1.8V
VDIG2 (300mA) VDDS_PLL_MPU (25mA) 1.8V
VDIG2 (300mA) VDDS_OSC (10mA) 1.8V
VAUX1 (300mA) VDDA1P8V_USB0/1 (50mA) 1.8V
VDD3 SMPS (100mA) Not Used -

Table 1: Power supplies to AM335x from TPS65910A3 PMIC


Boot Configuration

Various boot configurations can be set using the pull up / down resistor combinations provided on the SYS_BOOT pins (LCD_DATA0..15). Boot configuration pins are latched upon de-assertion of PORz pin.

The default settings for the TMDSSK3358 is 01_00XX_XXXX_XX11_0111b. This corresponds to a boot sequence of:

  1. MMC0
  2. SPI0
  3. UART0
  4. USB0

See the TMDSSK3358 schematic for more details. Refer to the AM335x TRM and data sheet for the definitions of each of the sysboot signals.

I2C Port Address Assignments

Information on I2C address assignments are provided below.

AM335x STARTER KIT (TMDSSK3358) Function AM335x I2C Port Address
Baseboard ID memory I2C0 0x50
AM355x PMIC Control I2C0 0x2D
AM355x PMIC Smart Reflex Control I2C0 0x12
Accelerometer Control I2C0 0x18
Audio Codec I2C0 0x1B
Capacitive Touch screen I2C0 0x38

Table 2:I2C Bus Addresses

Memories Supported

The TMDSSK3358 design supports on-board memories like DDR3 SDRAM and Board ID EEPROM. It also supports an SD card socket.


DDR3 SDRAM memory design is provided by using a 2 Gb single chip solution (MT41J128M16JT-125) from Micron. It is internally configured as a16 Meg x 16 x 8 bank memory. A separate Regulator to supply the DDR reference power to the AM335x and the VTT termination voltage to the termination components is provided in the design. The VIO_SMPS output from the PMIC is programmed to provide the required 1.5V to the DDR3 SDRAM.

Board Identity Memory

The board contains a serial EEPROM with the board specific data which allows the processor to automatically detect which board is connected and the version of that board. Other hardware specific data can be stored in this memory as well. The part number of the memory device used is CAT24C256WI-GT3. See the Configuration/Setup section for details on the data in this memory.

Name Size Contents
Header 4 MSB 0xEE3355AA LSB
Board Name 8 Name for board in ASCII “A335X_SK” = AM335x TMDSSK3358Board
Version 4 Hardware version code for board in ASCII “1.2B” = rev. 01.2B
Serial Number 12 Serial number of the board. This is a 12 character string which is:

WWYY4P19nnnn where: WW = 2 digit week of the year of production YY = 2 digit year of production nnnn = incrementing board number

Configuration Option 32 Codes to show the configuration setup on this board. For the available EVM’s supported, the following codes are used:

ASCII “SKU#00” = default configuration Remaining 26 bytes are reserved

Available 32720 Available space for other non-volatile codes/data

Table 3:I2C Configuration


The Micro SD/MMC0 port is provided with a card socket SCHA5B0200. This is a standard Micro SD/MMC Card type of connector which is of the low profile compact type. It is connected to the MMC0 port of the AM335x processor. Check the AM335x data sheet and TRM for supported card types/densities.8Gb SD cards are tested with this design. The Pin assignment is as given below.

Pin No Memory Card PIN No.
uSD#1 DAT2
uSD #3 CMD
uSD #4 VCC
uSD #5 CLK
uSD #6 GND
uSD #7 DAT0
uSD #8 DAT1
uSD #9 GND
uSD #10 CD

Table 4: SD/MMC0 Connector Pin Details


TMDSSK3358 has two Giga bit Ethernet transceivers. AR8031-AL1A from Atheros is used as a single port, tri speed PHY. A single 3.3V is enough to power this PHY and the other voltages required were generated internally. Reset for both the chips are driven by the SYS_WARMRESETn signal through a SN74LVC1G07 buffer.Both the PHYs have individual 25MHz, 50ppm crystal as their clock source. The 25MHz Clock out of the EMAC1-PHY port has been connected to the XTLI of the EMAC2-PHY as an optional clock input.

  • Note: The Starter Kit EVM PCB does not support external delay for the clock signals on the RGMII interface. The AR8031A PHY can be setup to use internal clock delay mode once booting is complete. Therefore there may be problems in function/performance when booting in Gb mode or when running Gb Ethernet Mode before the AR8031A PHY is configured properly. See the Starter Kit Errata.

For both the PHYs, mode selection pins MODE [3:0] are set as “0000” to operate it in 1000 BASE-T, RGMII mode. The PHY address for the EMAC1-PHY and EMAC2-PHY are 00100 and 00101 respectively.The interrupts from the both PHYs are connected to both the Non Maskable Interrupt pin and to the processor GPIO pins.

The Wake On LAN interrupts from the both PHYs are connected to the EXT_WAKEUP signal of the processor as an option.

Pin No Signal Name Description
1 DGND Ground
2 NC No connect
D2 GND Ground
D3 GND Ground
D4 PHY_ LED_1000n 1000 Base-T LINK LED signal

Table 5: 10/100/1000 Ethernet1 Pin Details



Micro AB USB port is provided as an upstream port of the USB HUB USB2412. This is used for USB to JTAG and USB to UART conversion applications through the downstream port 1 of the HUB. FT2232L is used for the USB to UART and JTAG conversion applications. The Downstream port 2 of the Hub is connected to USB port 0 of the AM335x.

The USB to UART/JTAG converter (FT2232L) has 32 configurable multifunction pins. A 16 bit, serial EEPROM 93LC56B from MicroChip is used to store the configuration data. Some of the pins from ADBUS [7:0] and ACBUS [7:0] are configured as JTAG and Reset signals. These JTAG pins from the FT2232 IC are connected to the dedicated processor JTAG pins and as well to the optional JTAG connector.

The Micro AB USB pin out details are provided below.

Pin No Signal Name Description
4 NC (USB_ID) No connect
5 DGND Ground

Table 6: Micro AB – USB0


The USB port1 of the AM335x is connected to the USB type A connector. USB power (5V )is provided to this connector through a buck-boost converter circuit.

Pin No Signal Name Description
4 DGND Ground

Table 7: USB A Type – USB1

Audio Codec

The TLV320AIC3106 is a low-power stereo audio codec with stereo headphone amplifier from TI. CLKOUT1 of the processor is sourcing the master clock of the codec (24Mhz). The CODEC I2C is capable of supporting both the standard and fast modes. I2C address of the codec is configured as 0011011. MCASP1 interface of the processor is connected to the audio interface of the codec. The stereo audio output is terminated in a stereo headphone Jack. The Pinout assignments for the headset jack are provided below.

Pin No Signal Description
1 AGND_AUD Analog Ground
3 HS_SPKRP Headset stereo LOUT
10 NC No Connect
2 HD_SPKRP Headset stereo ROUT

Table 8: Headset Jack


WLAN is no longer populated or supported on the AM335x Starter Kit. For TI WLAN support, consider using the AM335x EVM (TMDXEVM3358) along with WiLink8 module (WL1835MODCOM8B) which is sold separately.

User LEDs

The Four User LEDs implemented are D1-D4 in the user panel area. These are driven by the GPIOs from the AM335x.

All the user LEDs are green in color.

User Keys

This design has 4 user keys SW1,SW2,SW3 & SW4, three of them connected directly to the GPIO bank2 of the processor (Keys 2,3 & 4) and one of them (Key 1) connected to the GPIO bank0 of the processor.

Apart from the above four user keys, the design also has a button to interrupt the processor via the non maskable interrupt pin.


The LIS331DLH is an ultra low-power high performance three axes linear accelerometer used in TMDSSK3358 board. The accelerometer is mounted closer to the center of the board as to allow the most useful/dynamic data. The accelerometer is connected via I2C0 of the processor. The I2C(0) address is 0011000b.

Pin Use Description

The Pin use description file provides us the information on the pin functionality mode selected. The pin mux utility file is found here Pin Mux Data File

GPIO Definitions

See the updated pinmux document Pin Mux Description which shows the use case columns for GPIOs.

Board Expansion Connectors

The SPI0 and the I2C0 ports are extended through the connectors J11 and J8 respectively. SPI0 Expansion header pinout is provided below.

Pin No Signal Description
1 V3_3D Power 3.3V supply
2 AM335X_SPI0_CS0 SPI0 Chip Select 0
3 AM335X_SPI0_D1 SPI0 Data 1
4 DGND Ground
5 AM335X_SPI0_SCLK SPI0 Clock
6 AM335X_SPI0_D0 SPI0 Data 0

Table 9: SPI0 Expansion Header

I2C0 Expansion header is provided below.

Pin No Signal Description
1 DGND Ground
3 AM335X_I2C0_SCL I2C0 Clock
4 V3_3D Power 3.3V supply

Table 10: I2C0 Expansion Header


TFT color LCD module from Newhaven Display NHD-4.3-480272MF-ATXI#-T-1 with resistive touch screen shall be used as the LCD display for the TMDSSK3358 design. It is 4.3 inches wide and it has a built in driver and no controller is required. It has 480 X 272 pixels and supports up to 16.7M colors. This LCD supports white LED backlight. 24bit RGB signals, control signals and Resistive touch screen signals are terminated in a flex PCB with a 40 pin connector that fits into the TMDSSK3358 main board using a mating connector.

40 pin LCD connector pinout is provided here.

Pin No Signal Description
1 LED- Backlight LED power supply GND
2 LED+ Backlight LED power supply voltage
3 DGND Ground
4 VCC 3.3V LCD Power Supply
5 R0 Red Data0
6 R1 Red Data1
7 R2 Red Data2
8 R3 Red Data3
9 R4 Red Data4
10 R5 Red Data5
11 R6 Red Data6
12 R7 Red Data7
13 G0 Green Data0
14 G1 Green Data1
15 G2 Green Data2
16 G3 Green Data3
17 G4 Green Data4
18 G5 Green Data5
19 G6 Green Data6
20 G7 Green Data7
21 B0 Blue Data0
22 B1 Blue Data1
23 B2 Blue Data2
24 B3 Blue Data3
25 B4 Blue Data4
26 B5 Blue Data5
27 B6 Blue Data6
28 B7 Blue Data7
29 GND Ground
30 PCLK Data Sample clock signal
31 DISP Display ON/OFF signal
32 HSYNC Line Sync signal
33 VSYNC Frame Sync signal
34 DE Data enable
35 AVDD No connect
36 GND Ground
37 XR Touch Panel Right
38 YD Touch Panel Down
39 XL Touch Panel Left
40 YU Touch Panel Up

Table 11 :LCD Connector

EVM Important Notices

NoteNote: The Standard Terms And Conditions for TI Evaluation Modules can be downloaded from here:


This Hardware User's Guide is prepared by using the following documents as references.

  1. AM335x Sitara ARM Microprocessors TRM (SPRUH73)