I have a PIC between a RS232 and a RS485 that only check & calculates =
CRC values and respond to only few commands (e.g. Error Status and =
Firmware Version). All the other data is just passed on to the slaves on =
the RS485 network together with the CRC value.=20
If I power up the board...the fist data request to the firmware or to =
any other slave on the RS485 network returns "garbage". The follow-up =
request is always correct (Just very little CRC errors on slaves that =
are very far from the master unit - acceptable)

I expect the problem to be at the return data of the RS232 because the =
PIC respond to the commands the first time. If the CRC value is not =
correct or the PIC received "garbage" then it would just return to =
standby and the computer will retry.

I compensate for this by reading the firmware version from the PIC every =
time the software on the computer starts. The PIC or RS232 returns =
"garbage" (which I dont display) and after that the system works fine. I =
have a problem when the master unit is switched on when the software is =
already running.

Any suggestions?

Francois

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