In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Frasse wrote:

Hi,

I have recently bought the book Programming the SX Microcontroller by Gunther Daubach. 
My special interest, just now, is the UART implementation described in tutorial TUT40. 
Has anyone else had problems with getting this to run cleanly? 
I have used the sourcecode, downloaded from the Parallax site so there should not be any typos. 
I have found one error myself in both the printed version and the downloaded code (if my math is correct) and that is in the values for various baud rates. 
For 9600 baud the value for start_delay should read 32 + 16 + 1 instead of the shown 16+8+1. 
I have however tried the program using different baudrates and none seem to work. 
At reset it will produce garbage output, seemingly at random. 
By commenting out the call get_byte in the main program loop, it will stop the seemingly random output and instead, after each reset, it will provide an output with some similarities of the expected hello string, but with a majority of the characters garbled. 
Apart from altering the value for start_delay for the 9600 baud setting, my only change is that the VP is connected to a MAX232 driver circuit. As this will invert the signals I have tried removing the negation of the signal in the movb tx_pin,/tx_low.6 statement but this does not make any visual difference. Any and all help would be appreciated.

Regards
Frasse

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