Introduction to C5545 BoosterPack Board
27
SPRUI90 – September 2016
Copyright © 2016, Texas Instruments Incorporated
TMS320C5545 BoosterPack Hardware
2.13 I2C Interface
The C5545 BoosterPack provides an I2C interface that connects the AIC3206 audio CODEC (U9), an
OLED Display connector (J11), four INA219 current monitoring devices (U4, U5, U23 and U30) and the
LaunchPad header (J7, pin 9 and 10). Linking to the LaunchPad allows the DSP to access any I2C
devices on the LaunchPad and the LaunchPad MCU to access any I2C devices on the C5545
BoosterPack.
A level translator (U6 - TCA9517DGKR) is used between C5545 and LaunchPad/current monitoring
devices because IO voltage of LaunchPad/current monitoring device are 3.3 V while the C5545 DSP IO
voltage is 1.8 V.
For each individual device’s I2C address, see
in
Figure 25. I2C Interface
The I2C bus is shared by the C5545 BoosterPack and the Launchpad. While this allows the Launchpad to
access the I2C devices on the BoosterPack (OLED, CODEC, INA219 current measurement devices), it
requires configuration for the C5545 to boot properly and for the Launchpad device (ex MSP432) to
access the bus.
Before booting from the SD card, the C5545 boot-loader polls the I2C bus looking for an I2C EEPROM
with valid boot image. If the I2C signals are held low by the Launchpad or are not configured as I2C
signals, then the C5545 bootloader can get stuck waiting for the I2C bus to become ready, and may never
boot from the SD card.
Additionally, after the C5545 bootloader polls the I2C bus (even though no I2C EEPROM is present on the
board), the C5545 must perform a Start and Stop condition on the I2C bus before the attached Launchpad
can access the devices on the I2C bus. Examples of this configuration (provided in the diagnostics
software.Care:
http://www.ti.com/tool/BOOST5545ULP#Software
) must be taken to ensure that any
attached Launchpad drives I2C signals as GPIO outputs driven high or configures them as I2C pins (open
drain). This must be completed before releasing soft reset to the C5545 BoosterPack.
NOTE:
I2C address conflict: Since the I2C address of temperature sensor used in the CC3200
LaunchPad (0x41) is same as I2C address of INA Device (U30 – 0x41) on C5545
BoosterPack. Care should be taken in software while accessing this I2C slave device when
BoosterPack is connected with CC3200 LaunchPad.