Hi Everyone,
I am currently having an issue when using UART in LPM3 on the MSP430F5419A. If i send a burst amount of characters (from Hyperterminal) to the MSP, and have the MSP reflect the characters, it only reflects them for a small amount of time (usually around 10 characters are reflected) before the MSP no longer returns the characters to Hyperterminal. From what I can tell, the MSP undergoes some sort of framing error as several bits (UCFE, UCOE and UCRXERR) in the UCA0STAT register are set, when using the MSP430-FET430UIF to debug. This seems to prevent the MSP from receiving anymore characters, making the RX unusable until it is reprogrammed.
I have used a logic analyzer to ensure all the data being sent to the MSP is intact (which it is).
I noticed in the errata sheet there is a potential problem "SMCLK comes up fast on exit from LPM3 and LPM4". However I do not believe this is the problem since the same issue occurs in LPM1 and LPM2 as well.
The only methods of preventing these errors I have found (so far) is to never enter any Low Power Mode or to reduce the clock frequency from 20MHz to 8MHz, both are extremely undesirable for this project.
Other information:
Board rate: 115200
Core voltage: PMM Core Voltage 2 (1.75V)
If anyone has any insight as to why this UART RX problem is occurring, it would be much appreciated.
Kind Regards,
Jake