The problem I am facing is quite weird but seems real. When I connect STM32F429ZI to a radio we developed around CC1310 from TI via UART, I noticed that after flashing new firmware into STM32F429ZI or a cold start, I have to reset CC1310 to get UART communication between those two, specifically, sending data from STM32F429 to CC1310 but not the other way around, to work.
After much hassle, the problem is deemed as a compatibility issue. I was able to reproduce the problem with following test setup:
STM32F091RC, periodically sends data out of UART, and expects receiving the whatever it sends out
CC1310, flashed with uart echo example from reference documentation. It sends back whatever it receives.
UART pins and GND are connected with short wires directly.
After flashing firmware into STM32F091RC, I will have to reset CC1310 to get such setup to work.
However, I didn’t observe such problem between MSP430 and CC1310 both of which are from the same vendor TI.
I am under the impression that UART is an ancient and very robust interface, did I miss anything when connecting those two MCUs?
I reported the problem on TI’s support forum, but also want to start a thread here, just in case there is something particular about how UART is setup by Mbed on STM32 MCUs.