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Functional Blocks Description
7
SPRUIF8 – June 2017
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Copyright © 2017, Texas Instruments Incorporated
AM438x ePOS EVM Hardware
3.7
USB
The AM438x ePOS EVM supports two USB ports. The USB ports are connected to a microAB connector
and a standard type-A connector. The ESD device, TPD4S012, and common choke filter, ACM2012
(TDK), are used on the USB signals before they are connected to the AM438x pins. The ID pin of the
microAB connector can be tied to ground through a J24 jumper to look like a B device.
3.8
Connectivity
The AM438x ePOS EVM supports MCS COM8 form factor wireless boards from TI through the J21 COM
connector, which is a Samtec
®
card edge-type connector, part number MEC6-150-02-S-D-RA1. This
connector supports COM8 boards; more details are in the MCS COM8 board documents.
The COM connector requires 3.6 V, 442 mA on the power supply. Therefore a TPS79501 LDO regulator is
used to provide this voltage supply from the base 5.0-V supply.
The signals on the COM board are all 1.8-V voltage level. Therefore voltage translators are placed to
convert to and from 3.3 V of the AM438x rail for a particular signal that is running at 3.3 V.
3.9
UART
This EVM supports two UART ports, UART0 and UART1. The UART0 port from the processor is
converted to USB using the FT2232HL USB-to-UART bridge. UART1 is terminated on a DB9 connector
using the MAX3243 RS-232 transceiver between the AM438x and the DB9 connector. UART0 can also be
optionally terminated with a DB9 connector and a RS-232 transceiver. The RS-232 and DB9 connector
s
are unpopulated on the board.
3.10 ADC
The analog inputs to the AM438x device are terminated on the J36 connector, where a magnetic-stripe
assembly must be connected.
3.11 Smart Card
There is a full smart card connector FCI, part number 52400-25ALF, on the EVM. There are also three
SAM card sockets onboard. A TCA5013 Smartcard PHY controls these cards and is controlled by I2C2
from the AM438x.
The PHY I2C address is set to 0x3E.
3.12 Camera
Camera interface from the AM438x processor is terminated on the 12x2 header J15. The custom-made
camera module from TI shall be interfaced with this header. This camera module is on a separate camera
board that attaches at a right angle, so that the camera can face horizontally when the ePOS EVM is
laying on a testbench.
The I2C address set to camera module is 0x30.
3.13 Audio
This EVM uses an audio codec from TI, part number TLV320AIC3111, for the audio input and output. This
audio codec is connected through the McASP1 and I2C interfaces to the AM438x. The microphone is
implemented as a 3.5-mm jack with stereo connection. Speaker out is implemented with integrated
speakers. The PUI speakers are attached to the PCB and their solder lugs are connected to the
throughhole connections for each speaker. The audio codec reset is driven by the board system reset,
SYS_RESETn, and an individual reset signal that is controlled by a GPIO of the AM438x.
3.14 Printer Header
This EVM has a 2 × 12 header to connect to an external printer. The header connects several GPIOs, SPI
buses, and PWM signals to control a printer.