stk500 is an Erlang implementation of enough of the STK500 protocol to talk to an Arduino.
% Open the serial device attached to the Arduino
% The Diecimila uses 19200
{ok,FD} = stk500:open("/dev/ttyUSB0", [{speed, 19200}]),
% Read a hex file generated by the Arduino IDE
%
% hex_file/1 returns a list of binaries as read from the
% file (16 bytes). It's faster to use 128 bytes chunks.
Hex = stk500:hex_file("test/counter.cpp.hex"),
Bytes = stk500:chunk(Hex, 128),
ok = stk500:load(FD, Bytes),
stk500:close(FD).
test/counter.cpp.hex is a compiled hex file for testing, generated
from the example in examples/counter/counter.pde. To call the example
code from Erlang:
1> counter:run(). % loops adding 1 to a counter
2> {ok, FD} = counter:start("/dev/ttyUSB0").
3> counter:read(FD).
{ok, 0}
4> counter:incr(FD).
ok
5> counter:incr(FD, 5).
6> counter:read(FD).
{ok, 6}
7> counter:set(FD, 3).
ok
8> counter:read(FD).
{ok, 3}
$ rebar3 compile
# running tests
# arduino is attached to /dev/ttyUSB2
STK500_SERIAL_PORT=/dev/ttyUSB2 rebar3 ct
The simplest way to dump the serial communications is by using strace. For example, on an Ubuntu system, to see how the Arduino IDE is calling avrdude:
# as root
cd /usr/share/arduino/hardware/tools
mv avrdude avrdude.dist
cat<<EOF>avrdude
#!/bin/sh
set -e
mkdir /tmp/arduino-$$
strace -e read=3 -e write=3 -v -o /tmp/arduino-$$/dump \
-e trace=open,close,read,write,ioctl \
/usr/share/arduino/hardware/tools/avrdude.dist $@
EOF
An example protocol dump is doc/protocol_trace.txt.
The STK500 protocol documentation can be found here:
http://www.atmel.com/Images/doc2525.pdf