# Setup Raspberry Pi Pico for MAC Address Display

## Intro

This guide explains how to set up a Raspberry Pi Pico with an OLED display to show the MAC address of a Raspberry Pi when powered on. This is useful for commissioning new Raspberry Pi usb-remote servers.

In particular, if you are using this at DLS, we expect the Pi Server to be deployed into a beamline instrumentation network. You need the Mac address of the Pi to create a DHCP reservation for it in Infoblox. Having the Pico display the MAC address means that your commissioning process is:

- Put a pre-configured Raspberry Pi usb-remote server microSD card in a Raspberry Pi and power it on.
- Plug the Pico into the Raspberry Pi USB port and wait for the MAC address to be displayed.
- Use the displayed MAC address to create a DHCP reservation in Infoblox.
- Take the Raspberry Pi to the beamline, connect it to the instrumentation network and power it on.

## Hardware Required

- Raspberry Pi Pico (with micro USB connector)
- A display for the Pico e.g. 1.3" I2C OLED Display
  - The next heading provides code for this specific display - other displays will need a small amount of code modification

![Raspberry Pi Pico with OLED display](../reference/images/pico-led.png)

## Code on the Pico

- flash the Pico with the UF2 for MicroPython from <https://micropython.org/download/RPI_PICO/>
- clone https://github.com/samveen/pico-oled-1.3-driver and copy the python files to the Pico root filesystem
- save the following code as `main.py` on the Pico root filesystem.

See <https://www.waveshare.com/wiki/Pico-OLED-1.3> for more details on using the display.

```python
import select
import sys

import PicoOled13

# Set up the poll object
poll_obj = select.poll()
poll_obj.register(sys.stdin, select.POLLIN)


def main():
    # Initialize the display
    display = PicoOled13.get()
    display.clear()
    display.text("Listening ...", 0, 0, 0xFFFF)
    display.show()

    sys.stdout.write("awaiting data ...\r")

    line = 0

    while True:
        # Wait for input on stdin, waiting for 1000 ms
        poll_results = poll_obj.poll(1000)
        if poll_results:
            # Read the data from stdin (read data coming from PC)
            data = sys.stdin.readline().strip()
            sys.stdout.write("received data: " + data + "\r")

            # Write the data to the display
            if len(data) > 0:
                if line == 0:
                    display.clear()
                display.text(data, 0, line * 10, 0xFFFF)
                line = (line + 1) % 7  # wrap around after 7 lines
                display.show()

main()
```

## Sample Results

When the Pico is connected to a Raspberry Pi usb-remote server, it will display output similar to the following:

![Pico displaying MAC address](./images/pico-mac.png)