Modbus stack for Microchip PIC

Question

Can someone suggest an open source implementation of a Modbus RTU Slave for a Microchip PIC18 processor? I\'m looking for an implementation of Modbus RTU for RS-232/RS-485,

Answer 1

I've implemented a Modbus RTU (and ASCII) slave for PIC18 but using USB instead of RS232/485. It would be very easy to convert to RS232/485 though as the protocol code only requires character transmit and receive functions. I can help you with this if required.

Take a look at my USB Modbus I/O page at http://www.fieldofcows.com/index.php?title=USB_Modbus_Interface to see if it meets your needs. The page includes a download link for the source code. The source is released under GNU GPL.