A small-footprint Modbus server crafted in assembler for Microchip PIC 18Fxxxx-series microcontrollers.
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packets
.gitignore
COPYING
JamodTest.java
Makefile
README
README.JAMOD.txt
ascii.asm
diag.asm
frame.asm
jamod.jar
modbus.asm
modbus.inc
modbus.rb
private.inc
rtu.asm

README

PIC Modbus
Copyright © 2006,2008  Peter Heinrich

This library constitutes a tiny Modbus server (slave) for the Microchip PIC
18Fxxxx-series of microcontrollers (16-bit), coded in assembler.  It relies on
the PIC-framework library.  Although the code relies on certain characteristics
and features specific to the 18Fxxxx family (e.g. access bank, relatively large
RAM storage area), porting it to other PIC types would not be impossible.

This server supports both ASCII and RTU modes, although RTU hasn't yet been
extensively tested.  Similarly, communication speeds above 19200 baud haven't
been tested rigorously.

Diagnostic commands documented in the Modbus specification are supported to
the extent allowed--some commands are necessarily application-specific.  In
fact, due to the mapping model of Modbus, most commands must be implemented
according to the requirements of the application.  This library simply provides
a framework on which to hang that code, handling the protocol, timing, and
error conditions.