Copyright 2023 (C) Peter McGoron.

This file is a part of Upsilon, a free and open source software project.
For license terms, refer to the files in `doc/copying` in the Upsilon 
source distribution.

__________________________________________________________________________

This manual describes the controller software programming. This guide does not
describe Verilog: see `verilog_manual.md` for that.

# Preqreuisites

You must know basic Linux shell (change directories, edit files with `vi`)
and basic SSH usage (sftp, ssh).

Knowledge of Micropython (a subset of Python) is required for scripting.

I assume that you have the controller running and accessable. See `docker.md`
for the easy quick-start guide.

# Programming in MicroPython

## Introduction to MicroPython

MicroPython is a programming language that is very similar to Python. It is
stripped down and designed to run on very small devices. If you have written
Python, you will be able to use MicroPython without issue. If you are not
a hardcore Python programmer, you might not even notice a difference.

Everything you need to know is [here](https://docs.micropython.org).

## Standard Library

There are two modules of the standard library: `mmio` and `comm`.

`mmio` are wrappers that handle reads and writes from MMIO pins. This file
is automatically generated by the build process. This file is generated in
the `gateware` directory (if you use the Docker build system, the file is
automatically copied to `boot/mmio.py`).

`comm` contains higher level wrappers for DAC and ADC pins. This module is
documented well enough that you should be able to read it and understand
how to use it.

# FAQ

## SCP Is Not Working

SCP by default uses SFTP, which dropbear does not support. Pass `-O` to all
SCP invocations to use the legacy SCP protocol.