vasile surducan wrote: > If you are using the hardware UART, there are some computations which tell's > you the error for various crystals. Take a deep look to the Stef's "usart > common.jal" from the distribution pack and to the microcontroller datasheet > USART section, you will find the formula for error detection and spbrg > computation. But 9600bps must work with 4MHz crystal or the internal > oscillator. The problem is the internal oscillator stability, not the > particular value of the oscillator.
vasile I am not using the hardware UART. The k107 backpack is a serial interface to a LCD. It uses 1 pin to communucate to the LCD and, in the version I have, only at 9600 Baud. I am using the serial_software lib and with a 20MHz clock it works very well. My goal was to get an LCD working on 8 pin chips, like the 12f509. I 'thought' that I could use the internal 4MHz clock to generate the 9600 Baud clock. I must have mis-read or understood incorrectly. > > However I've seen at least twice a situation when the usart common.jal does > not compute correct the spbrg value, without being able to catch the > problem. So the question for other guys is how they debug such kind of > errors as long there isn't a valid communication for terminal debugging? > > I didn't figure a usefull way of using "pragma error". Old jal had "pragma > test assert " which was a damn good feature. How do you use the "pragma > error" for debugging? I have seen that in some of the libs also but have not found anything else about how to use it. I probably missed it or, more likely, didn't understand it. :-( Thanks for the reply! Regards Wayne > Vasile > > > On 11/13/09, Wayne <[email protected]> wrote: >> >> Hi guys >> >> Finally made some progress on the k107 backpack. Thanks to a comment >> made by Rob, I tried a 20 Mhz resonator on the 16f628a and it finally >> displayed the 'correct' characters on the LCD. The same program did NOT >> work using 10,8 and 4 MHz resonators or with the 4MHz internal clock. It >> seems that the 20Mhz clock gets the 9600 baud rate correct while none of >> the others did. Has anyone else had problems getting the 9600 Baud Rate >> working? I am using the 'l' version of the compiler (compiled Aug 7 2009). >> >> I had hoped to use the k107 on a 12f509 using the internal clock but >> that does not seem to be possible now. >> >> Wayne >> > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/jallib?hl=en -~----------~----~----~----~------~----~------~--~---
