HiI know its possible to configure the serial H/W to handle a driver signal to serve an RS485 bus. Unfortunately, our board has the driver pin on a different port and therefore I had to do the trick by software.
I have modified at91serial.c that when ENDTX happend, it enables TxEMPTY interrupt and then if TxEMPTY happens, a private (configurable) callback routine is invoked. The driver works fine this way - unless there is the case that a transmitted message remains without answer. Then, upon the next send, I can see that my software sets the driver on but something puts it back imediately (app 230 us). This happens even before the first character is on line. But it is clearly related to the call to
cyg_io_write(..However, I can not find where the TxEMPTY interrupt is enabled. Is there a at91serial.c-Guru somewhere who could give me a hint where this happens and how I could fix it. Thanks and regards
Robert
at91_serial.c
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