Using Both Usart Problem With "modbus.c"

debi · Joined: 12 Jun 2012 Posts: 1

We use "modbus.c" driver for PIC1867J10 with single usart(only RDA). Now we want to communicate double uart(RDA-RDA2 both) with "modbus.c" driver. Is it possible, how?

RF_Developer · Joined: 07 Feb 2011 Posts: 839

Modbus.c ues more than one resource. The problem is not just the UARTs, its the timer(s?) modbus.c uses in RTU mode. I strongly suspect that modbus.c was written to be a highlander - there can only ever be one.

I assume your application has two or more Modbi, on one of which this code will be a slave, while on the other it is the master. Maybe some kind of Modbus repeater/extender? If so I think you are going to have to delve deep into modbus.c and sort it out for yourself. You'll have to make two versions of its control/data structures, and sort out the timer usage. Its certainly not a case of setting a natty flag and away you go.

RF Developer