TM4C123BH6PZ: Texas Instruments Tiva™︎ TM4C123BH6PZ Microcontroller (SE Part #: HUA34331) Query

TI Microcontroller is used to monitor
and controls the Mains 2 and Output Voltage feedback adc sensing, Heatsink
temperature monitoring for the Mains 2, RS232 Communication, PSU Error
detection, UPS hardware revision detection, UPS mode detection, Heart beat
generation and its error detection, CAN Bus Communication, Mains 2 SCR
Control, Mains 2 Phase Control and ECO Mode selection. Also MCU is
responsible for the Mains 2 Back feed (BF2) breaker control and status
monitoring. Microcontroller is powered through a 3.3V regulated Power supply
and running at 8MHz external oscillator for clock module.
Circuit explanation for Back feed operation:
MCU will generate a signal with 500Hz square pulse at
BACKFEED_ON_PULSE_1 which will inverted using U4530 and applied to
U4531 CLR (Pin-11) and a clock pulse of 380Hz was applied to U4531 CLK
(Pin 10). A delay circuit using U4530 will generate a 5secs delay and added to
clock pulse. Once both CLR and CLK signals are at Low level, the Output (Pin
1) of U4531 (SN74LV4040 - Binary Counter) will go to high level (5V) after 5
Secs delay. This high signal (BACKFEED_TRIGGER_STATUS_1) will turn on
the transistor T4532 to trigger the RL4530 relay coil to trip the Back feed (BF2)
breaker. This BACKFEED_TRIGGER_STATUS_1 (input signal) will be
monitored by the MCU using the Pin 29 (PA3/SSI0Fss). | Summary: We have
reworked and swapped the boards with the defective batch vs OK batches 20
Nos each and found failing only in the defective batches.
This is done in line with your defined datasheet procedure only.
We have seen this failure only in 35~36 Deg C.