[Dprglist] New Raspberry Pi RP2040 boards

[Murray Altheim]

Summary: There are two new, small and low-cost Raspberry Pi
computer boards based on a new RP2040 chip (developed by the
Raspberry Pi Foundation), now or soon to be available, along with
a new line of accessories and carrier boards. There's also two
RP2040 boards from Adafruit using their Feather and ItsyBitsy
form factors.

----

The RP2040 boards from Raspberry Pi are respectively called the Pico
and the Tiny2040 and are different from previous Raspberry Pis in that
they don't run a Linux operating system, they run either a single C/C+
or MicroPython program which is loaded (like an Arduino) over USB.

These boards are considerably smaller and lighter than other Pis, and
rather than dual-row GPIO pins their IO pins are spread around the
perimeter of the board.

The Pico is about the size of an Arduino Nano:

   Raspberry Pi Pico
   https://shop.pimoroni.com/products/raspberry-pi-pico     £3.60
   https://www.adafruit.com/product/4883 (loose headers)    US$5.00
   https://www.adafruit.com/product/4864 (no headers)       US$4.00

Pimoroni are releasing a series of support boards for the Pico, such
as:

    Pico Explorer Base (LCD, mini breakboard, motor drivers, etc.
    kinda nice for a small robot)
    https://shop.pimoroni.com/products/pico-explorer-base    £22.20

    Pico Breakout Garden Base
    https://shop.pimoroni.com/products/pico-breakout-garden-base   £12

The latter provides 4 I2C and 2 SPI sockets for their Breakout Garden
series of sensors, displays, etc.

The Tiny is about the size of a postage stamp, with 12 IO pins, 4 as
optional 12-bit ADC channels:

   Tiny 2040
   https://shop.pimoroni.com/products/tiny-2040             £8.40

[It's notably more expensive than the Pico.]

Adafruit has also packaged the RP2040 in both their Feather and
ItsyBitsy form factors:

   Adafruit Feather RP2040
   https://www.adafruit.com/product/4884                    NA (yet)
   Adafruit ItsyBitsy RP2040
   https://www.adafruit.com/product/4888                    NA (yet)

Here's a description of the 2040 CPU:

     About the RP2040

     The RP2040 microcontroller is a dual core ARM Cortex M0+ running at
     up to 133Mhz. It bundles in 264kB of SRAM, 30 multifunction GPIO
     pins (including a four channel 12-bit ADC), a heap of standard
     peripherals (I2C, SPI, UART, PWM, clocks, etc), and USB support.

    One very exciting feature of the RP2040 microcontroller are the
    programmable IOs which allow you to execute custom programs that
    can manipulate GPIO pins and transfer data between peripherals -
    they can offload tasks that require high data transfer rates or
    precise timing that traditionally would have required a lot of
    heavy lifting from the CPU.

As alluded to in that last paragraph, I'll be curious to see how any
of these RP2040 boards can be used as a slave processor when connected
to a Raspberry Pi, a topic we've been discussing a fair bit lately. In
the SDK documentation there's sections on how to connect to an RP2040
board from a Raspberry Pi over USB or GPIO, and how to connect to a Mac
over USB. It looks like the GPIO connection is over UART.

The Pimoroni Pico product page at:

   https://shop.pimoroni.com/products/raspberry-pi-pico

has a section at the bottom with links to some fairly extensive
documentation:

   * Raspberry Pi Pico Datasheet - An RP2040-based microcontroller board
   * RP2040 Datasheet - A microcontroller by Raspberry Pi
   * Hardware design with the RP2040 - Using the RP2040 microcontroller
     to build boards and products
   * Getting Started with Raspberry Pi Pico - C/C++ development with
     the Pico and other RP2040-based microcontroller boards
   * Pico C/C++ SDK - Libraries and tools for C/C++ development on the
     RP2040 microcontroller
   * Pico Python SDK - A MicroPython environment for the RP2040
     microcontroller

Quite exciting!

Cheers,

Murray

[Legal Notice: I hold no fiduciary interest in Pimoroni, Adafruit,
foamtiles.com or any other electronics or foam tile wholesale or retail
establishment.]
...........................................................................
Murray Altheim <murray18 at altheim dot com>                       = =  ===
http://www.altheim.com/murray/                                     ===  ===
                                                                    = =  ===
     In the evening
     The rice leaves in the garden
     Rustle in the autumn wind
     That blows through my reed hut.
            -- Minamoto no Tsunenobu