loopy-docs

# How to Program Loopy

In order to program Loopy, you need:
- an atmega328(p) chip
- an AVR programmer (an inexhpensive USBasp is perfectly fine, like the one [here](https://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=140_161_163&products_id=1233))
- a 10 to 6 pin adapter if your programmer is not supplied with one, like the one [here](https://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=140_161_163&products_id=2848)
- [avrdude](https://www.nongnu.org/avrdude/) correctly installed on your computer (installation are dependent on your OS of choice -- if you are on Mac, the easier way is to use [brew](https://formulae.brew.sh/formula/avrdude))

Once your computer is setup, you need to run three commands on your terminal.

The first command is mandatory to initialise the chip, and needs to be performed only on a blank chip. 

Once the initialisation is completed, the chip will work only if correctly connected to an oscillator: I strongly suggest to use the 6 pin header on the PCB to install the firmware.

## Fuses

If your chip has already a working copy of the firmware, you can skip this step. Otherwise, run:

```
avrdude -c usbasp -p atmega328p -B16 -U lfuse:w:0xFF:m -U hfuse:w:0xD9:m -U efuse:w:0xFF:m -U lock:w:0xFF:m
```

## Firwmare

The second command will upload the firmware on the chip:

```
avrdude -c usbasp -p atmega328p -U flash:w:<hex file location>
```

## EEPROM

The third command will setup the EEPROM, the portion of memory where the chip stores presets and config. The upload of the firmware will reset this location of memory, while running the following command will restore default values:

```
avrdude -c usbasp -p atmega328p -U eeprom:w:loopy.eep
```