Hands on with the Raspberry Pi Pico

Like many of us, on January 21st I woke up to a barrage of news about the new Raspberry Pi Pico.  Microcontrollers launch all the time, but this one caught everybody's imagination.  So I hopped over to Adafruit to order one before they sold out, and a few days later it showed up in my mailbox.

I must confess, I'm a sucker for cheap microcontroller boards.  In the past I have bought other cheap 32-bit MCUs, and regretted it.  I guess if you're selling assembled boards at $2-4, there's not much margin to pay for verification, documentation or QA. Put another way: things in the bargain bin are in the bargain bin for a reason.

(I'm not against cheap microcontrollers per se. For example I've now used about 20K of the Silicon Labs EFM8 microntrollers, at about $0.25 each.  They are excellent, but obviously Silicon Labs sells a staggering volume of these to pay for the engineering to back it up.)

So it was a delightful surprise when the Pico behaved perfectly out of the box, has a datasheet told me everything I wanted to know, and was running CircuitPython in a few minutes. Like a lot of other boards, it handles firmware updates by appearing as a USB filesystem. You copy the firmware onto the drive and it runs. Very straightforward; no special tools to get started. This is progress.


A couple of minutes later, having hooked it up to a Dazzler breakout board, I was looking at the Dazzler Python demos, all running identically.


CircuitPython performance is pretty good, but a little below the speed of the Adafruit M4, which is a similarly-clocked Cortex M4.  The Cortex M0 has no floating-point, so has to do software floating-point.

The M4 benchmark for reference:

Adafruit CircuitPython 6.2.0-beta.0-dirty on 2021-01-22; Adafruit Metro M4 Express with samd51j19
>>> import bench
0.0320129
1000 points took 32.0 ms

The Pico's M0 is quite respectable:

Adafruit CircuitPython 6.2.0-beta.1-56-g8789a2c8a on 2021-02-02; Raspberry Pi Pico with rp2040
>>> import bench
0.0419922
1000 points took 42.0 ms

So the next step was to lay out a board with everything hooked up properly. The board has:

• A Gameduino Dazzler module
• Two Wii joystick ports
• a microSD slot
• A socket for the Pico

The Pico drives the Dazzler over the SPI interface, but there's also a hookup for the Pico's UART port so it can run the Dazzler in text mode.

While I was doing this, I made a similar board for the Teensy. Likewise one for the Adafruit Feather footprint is coming next week.

Thanks for reading. The Pico board should be here by next Tuesday.