We're loosing serial bytes from PC to phone

Christian Vogel vogelchr at vogel.cx
Sun Mar 21 10:38:47 UTC 2010


Hi Harald,

>> send_to_phone(dlci=5): 0a 00 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d
...
>> l1a_l23_rx_cb:         0a 00 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f  
>> 10 11 12

> as you can see, there is a '00 01' missing between the '00' and the '02'.

Does the 16C750 do anything fancy to compensate for slow/fast clocks by
adjusting it's internal sampling points to the edges on the incoming data?

If he does, we might have a clock that's slightly off and the compensation
might fix that for anything except the 0-bytes which don't have any 0/1  
transitions.

To find out, one could use a lower baud-rate and adjust the divider until
the problem gets worse/goes away. And always check with a 2nd com-port on  
the PC
in parallel.

	Chris
		(just lurking, no compatible phone (yet))




More information about the baseband-devel mailing list