RP2040-Zero

[last updated: 2024-09-14]
MicroPython on RP2040
Thonny with RP2040
-----------------------------

This is a collection of information and procedures to get this device up and running.
I received my order of several, and am testing to see what works...

• The RP2040-Zero is a small board built around the RP2040 MCU.
  It is available from Waveshare and the usual import clone sources.
   
  • Specs:
    • 30 total GPIO, 4 of which can be analog
    • 15 GPIO available on castellated pcb side edges
          plus 6 more on the end
      9 GPIO available on solder pads on bottom of board
    • 264 KB SRAM
    • 2MB flash
    • 133 MHz clock
    • 2 SPI controllers
    • 2v SPI controllers
    • 8 PIO state machines
    • 16 PWM channels
    • QSPI bus controller supports up to 16 MB of external flash memory
  • GPIO Voltage tolerance:
    • This is squishy. The official specs apparently say that the I/O only handle 5v
    • However many online reports say you can get away with connecting directly to 5v devices...
  • On-board RGB LED is programmed with GP16.
  • The board has two pushbuttons: "boot" and "reset"
    Holding the boot PB when powering up the board puts it into "BOOTSEL" mode,
    in which it will show up on your host PC as a remote USB drive.
    However BEWARE because in this mode, the Only file you can transfer is the .uf2 firmware file...
  • The RP2040 has a "programmable I/O" system (PIO)
    that allows creating interfaces for custom hardware.
    [search for "rp2" module]
  • per wiki:
    " ... can be programmed in assembly, C, C++, Swift, Free Pascal, Rust, Go, MicroPython, CircuitPython, Ada and TypeScript. It is powerful enough to run TensorFlow Lite."

  -----------------------------

  
  .

• Startup:
  • The Pico/Zero cannot be programmed directly from the Arduino IDE.
  • First you must decide how you are going to program it, as listed above, there are several options.
    I'll be using MicroPython, and have no info on any other method.

  • Install MicroPython on the RP2040-Zero:
    • per Waveshare tutorial:
    • download (onto your host PC) the pre-built release binary from the link below:
      RPI_PICO-20240602-v1.23.0.uf2
      This is the latest release of the "firmware" file.
    • unplug all power from the zero, press and hold the boot PB, plug in the zero via USB to your host PC.
      A new drive "RPI-RP2" should show up in your file manager.
    • drag the MicroPython [firmware].uf2 file onto the RPI-RP2 drive.
      File transfer will take a few seconds,
      after which the zero will reboot into MicroPython,
      and the RPI-RP2 drive will disappear.
    • At this point the zero is running MicroPython.
      However all it's doing is sitting and waiting for instructions.

    Continue to:
    MicroPython on RP2040
    --------------------------------------------------

  • Random notes:
    • The "Raspberry Pi Zero" is a different board
      The "Raspberry Pi Pico" is a different board, though very similar...
    • Problem report from some forum:
      "It seems that on some units there's something slightly wrong with the crystal oscillator.
      Setting PICO_XOSC_STARTUP_DELAY_MULTIPLIER to 64 in the board file helps."

    -----------------------------

  • Links:
    • wiki for the RP2040 MCU: https://en.wikipedia.org/wiki/RP2040
    • Waveshare: https://www.waveshare.com/wiki/RP2040-Zero
    • Waveshare tutorial on python: https://www.waveshare.com/w/upload/b/b0/Pico_python_sdk.pdf
    • https://spotpear.com/index/product/detail/id/906.html
    • spotpear user guide: https://spotpear.com/index/study/detail/id/636.html
    • the one I ordered: https://www.aliexpress.us/item/3256806921643389.html
    • MicroPython download for pico (and zero): https://micropython.org/download/RPI_PICO/
    • interesting approach to running programs... https://stackoverflow.com/questions/69271473/using-python-and-pyserial-t...
      https://blog.rareschool.com/2021/01/controlling-raspberry-pi-pico-using....
    • for future... SPI on python on rPi: https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial/all
    • QSPI NOR memory (just one 4Mb example of many available): https://www.microchipdirect.com/product/SST25PF040C-40V/SN?samples=true
    • https://community.element14.com/products/raspberry-pi/b/blog/posts/raspb...
    • OLED driver on github: https://github.com/gavinlyonsrepo/SSD1306_OLED_PICO

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