# baud
Serial port with RTU and TCP-to-RTU support.
## Installation and Usage
1. Add `baud` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[{:baud, "~> 0.3.0"}]
end
```
2. Build & test it:
See [NOTES](NOTES.md) for platform specific instructions on setting up your development environment.
```shell
#Serial port names are hard coded in test_helper.exs
#A couple of null modem serial ports are required
#com0com may work on Windows but not tested yet
./test.sh
```
3. Use it:
```elixir
alias Baud.Enum
["COM1", "ttyUSB0", "cu.usbserial-FTYHQD9MA"] = Enum.list()
```
```elixir
#Do not prepend /dev/ to the port name
{:ok, pid} = Baud.start_link([portname: "cu.usbserial-FTYHQD9MA"])
:ok = Baud.write(pid, "Hello!\n");
{:ok, "Hi!\n"} = Baud.read(pid, 4, 400);
{:ok, "Hi!\n"} = Baud.readln(pid, 400);
{:ok, 24} = Baud.available(pid);
:ok = Baud.wait4rx(pid, 400)
:ok = Baud.discard(pid)
:ok = Baud.echo(pid)
:ok = Baud.close(pid)
```
```elixir
alias Baud.Sock
#Do not prepend /dev/ to the port name. Mode defaults to :raw
{:ok, pid} = Sock.start_link([portname: "ttyUSB0", port: 5000])
#use netcat to talk to the serial port
#nc 127.0.0.1 5000
:ok = Sock.stop(pid)
```
```elixir
alias Baud.Sock
#Do not prepend /dev/ to the port name.
{:ok, pid} = Sock.start_link([portname: "ttyUSB0", port: 5000, mode: :rtu_tcpgw])
#modbus TCP commands sent to 127.0.0.1:5000 will be forwarded as RTU to serial port
:ok = Sock.stop(pid)
```
```elixir
{:ok, pid} = Baud.start_link([portname: "cu.usbserial-FTVFV143", baudrate: 57600])
#write 1 to coil at slave 2 address 3200
:ok = Baud.rtu(pid, {:wdo, 2, 3200, 1}, 400)
#write 0 to coil at slave 2 address 3200
:ok = Baud.rtu(pid, {:wdo, 2, 3200, 0}, 400)
#read 1 coil at slave 2 address 3200
{:ok, [1]} = Baud.rtu(pid, {:rdo, 2, 3200, 1}, 400)
```
## Releases
Version 0.3.0
- [x] Integration test script and modport panel
- [x] Added test.sh to isolate tests run
- [x] RTU master, slave, and tcpgw loop modes
- [x] Serial port export to socket in raw, text, and modbus mode
- [x] RTU API matched to `modbus` package (1,2,3,4,5,6,15,16)
- [x] Improved timeout handling for shorter test times
Version 0.2.0
- [x] Interactive RTU: read/write up to 8 coils at once
Version 0.1.0
- [x] Cross platform native serial port (mac, win, linux)
- [x] Modbus (tcu-rtu), raw and text loop mode
## TODO
- [ ] loop* tests still show data corruption when run all at once
- [ ] Implement Modbus ASCII support (no available device)
- [ ] Implement DTR/RTS control and CTS/DSR monitoring
- [ ] Implement separate discard for input and output buffers
- [ ] Unit test 8N1 7E1 7O1 and baud rate setup against a confirmed gauge
- [ ] Get port names required for unit testing from environment variables
- [ ] Implement a clean exit to loop mode for a timely port close and to ensure test isolation
- [ ] Improve debugging: stderr messages are interlaced in mix test output
- [ ] Improve debugging: dev/test/prod conditional output
- [ ] Move from polling to overlapped on Windows
- [ ] Research why interchar timeout is applied when reading a single byte even having many already in the input buffer. Happens on MAC.
- [ ] Research how to bypass the 0.1s minimum granularity on posix systems
- [ ] Research Mix unit test isolation (OS resources cleanup)
- [ ] Research printf to embed variable sized arrays as hex strings
