My own experiences with the UART programming is that the internal RC clock is way too unstable and exact to produce a stable communication. With 4MHz RC clock I was unable to establish a reliable link with 9600 Baud, while with the same code and an external 8 MHz quarts even a baudrate of 115KBaud was no problem. At least you'll need an external 32KHz clock-quartz and some timer-driven code to build something like a software-PLL to keep the RC oscillator in the proper range.
JMGross ----- Ursprüngliche Nachricht ----- Von: Daniel Flor <[email protected]> An: [email protected] Gesendet am: 01.Juni.2009 00:37:51 Betreff: [Mspgcc-users] problem in comunication UART Hello, At the moment I'm only testing the UART communication with the AC4490( a transceptor ) and it seems to work, I made a mirror with the UART. The transceptor send a char for UART, and UART sends it back to the transceptor. But, always when I send the following sequency by transceptor, one to nine three times, (123456789123456789123456789) it always went back from UART (123456781234567123456) i.e. missing 9, 8, 7. The same pattern happens with any sequency with many characters. I think it would be a problem with oscilator, because I'm not using external oscilators. The frequency of operation in my test was 4.13MHz and UART velocity was 9600baud (for both, AC4490 and UART). I thought that the problem verified in UART would be due to J-TAG, but I can't verify it because when I remove J-TAG, the transmission don't occur. Please, someone have any idea? Thanks Daniel
