# PyCom basic HowTo
###### tags: `Tools` `Labs`
OLD... better this https://hackmd.io/@pmanzoni/rkTKjifUL
This document describes:
1. the basic information required to set up a development environment, and
2. the programming workflow for a Pycom device, in our case the LoPys.
The main goal is to gain access to the REPL. REPL stands for Read Evaluate Print Loop, and is the name given to the interactive MicroPython prompt that is accessible on the Pycom Devices. Using the REPL is by far the easiest way to test out python code and run commands.
More infos about REPL can be found here: https://docs.pycom.io/chapter/gettingstarted/programming/repl/
You must have Python3 and `pip` installed in your computer.
* installing Python3 -> https://www.python.org/download/releases/3.0/
* installing `pip` -> `sudo apt-get install python3-pip`
## Installing mpy-repl-tool
mpy-repl-tool is the software tool that we will use to connect and control a LoPy (http://mpy-repl-tool.readthedocs.io/en/latest/index.html).
To install it you have to execute:
$ python3 -m pip install mpy-repl-tool
## Getting started with mpy-repl-tool
Plug-in your LoPy device in a USB port and wait a few seconds until the LED starts blinking in blue.
_NOTE: If you are using an OS inside a virtual machine, remember to tell the host machine to associate the device with your VM_
$ python3 -m there detect
This command will list the serial ports and "hopefully" :smiley: will automatically find your LoPy board.
OK, now you are ready to start!
## Some usage examples
* to get a list of the files on the LoPy do: `$ python3 -m there ls -l /flash/*`
$ python3 -m there ls -l /flash/*
---------- 0 0 34B 1980-01-01 01:09:16 /flash/main.py
---------- 0 0 29B 1980-01-01 01:09:18 /flash/boot.py
> The filesystem has ``/`` as the root directory and the available physical drives are accessible from here. They are:</br>
> ``/flash`` – the internal flash filesystem</br>
> ``/sd`` – the SD card (if it exists)
* read the contents of a file on the LoPy:
```python3 -m there cat /flash/somefile```
* copy multiple files from your computer to the LoPy:
```python3 -m there push *.py /flash```
* backup all the files on the LoPy to your computer
```python3 -m there pull -r \* backup```
* finally, to start a serial terminal and get access to the [REPL](https://docs.pycom.io/chapter/toolsandfeatures/repl/) prompt add, exec:
```python3 -m there -i```
A detailed list of commands can be found here: http://mpy-repl-tool.readthedocs.io/en/latest/commandline.html
# Typical Lopy device workflow
A typical workflow is the following:
1. Create a folder on your computer
1. Plug your device into your USB port and exec:
```$ python3 -m there detect```
1. Write your code on your computer
1. Copy the code files from your computer to the LoPy
```$ python3 -m there push *.py /flash```
1. Start a serial terminal and get access to the REPL:
```$ python3 -m there -i```
1. Execute the code on the LoPy: e.g., `>>> import file`
# Exercise: Let's see if it works
Execute the following code on your LoPy
RED = 0xFF0000
YELLOW = 0xFFFF33
GREEN = 0x007F00
OFF = 0x000000
pycom.heartbeat(False) # Disable the heartbeat LED
def flash_led_to(color=GREEN, t1=1):
**Hint: save the code in a file named "test.py" for example and, in the REPL console, write ```import test```**
# How to
Below you'll find some generic information about how to connect and work with LoPys.
## Connect to a LoPy via WiFi
You can have access to the REPL also via a WiFi connection. Your LoPy by default works as a WiFi access point. Search an SSID that looks like `lopy-wlan-XXXX`; the password is `www.pycom.io`:
Then, you can access via telnet or via tools like Filezilla.
### Accesing via `telnet`:
```telnet 192.168.4.1```and use as user/password the values *micro*/*python*.
### Accesing via Filezilla
If you want to interchange files with your LoPy you can use a tool like Filezilla:
1. Connect to device's WiFi (see above):
2. Go to top menu `File > Site Manager...` and use as the user/password pair the values *micro*/*python*:
They are different ways to reset your device. Pycom devices support both soft and hard resets.
A **soft reset** clears the state of the MicroPython virtual machine but leaves hardware peripherals unaffected. To do a soft reset,
* press Ctrl+D on the REPL or
>>> import sys
A hard reset is the same as performing a power cycle to the device. In order to hard reset the device, press the reset switch or run:
>>> import machine
If a device’s filesystem gets corrupted, it can format it by running:
>>> import os
More details here: https://docs.pycom.io/chapter/toolsandfeatures/bootmodes.html