Receiving my Buspirate I was curious how difficult it would be to install Micropython on it.
As for why, I feel Micropyhton could be an interesting alternative to the current firmware, if Buspirate features are implemented as Micropython modules. That would give people the possibility to use a programming language for debugging and testing.
It is surprisingly easy to switch between Micropython and the Buspirate firmware.
All one has to do:
Install Micropython:
- Get a copy of Micropython for the RP pico, readily available here:
https://micropython.org/download/RPI_PICO/ - Keep the small rear-side button on the Buspirate pressed and (re)plug the USB-C cable.
- A flash-drive appears on the computer, named RPI-RP2. Open it and copy the uf2 file into it.
- Do not unplug, flashing will take place automatically directly after the file transfer was performed (takes about 5 seconds).
- The display and LEDs turn off (don’t panic) Micropython has (yet) no idea of the peripherals .
- You will notice the uf2 file on the flash drive is gone. Flashing is complete.
- Repower the Buspirate (for good measure, not really needed).
- The host computer will recognize a serial device. Connect to it in the same way, like you connect to the Buspirate.
- Congrats, you just logged in the interactive Micropython shell.
Little Demo?
Micropython comes already with some modules and enough functions to get some stuff out-of-the-box working. E.g. the infamous version of “hello world” for microcontrollers aka led-blinking.
The following code will just do that (you can copy & paste it into the shell using CTRL-E to enter paste mode and CTRL-D to execute it):
from machine import Pin
from neopixel import NeoPixel
from random import randint
pin = Pin(17, Pin.OUT) #GPIO17 levelshifter for the LEDs (3.3V-5V)
shift_enabler = Pin(21, Pin.OUT) #GPIO21 shift enabler pin
np = NeoPixel(pin, 18) # amazing there are 18 little blinkelights
shift_enabler.off() #inverse logic
for x in range(100):
np.fill((randint(0,255),randint(0,255),randint(0,255))) #just random colours
np.write() #set them
machine.lightsleep(250) #sleep for 250ms to avoid seizure
np.fill((0,0,0)) #set to 0 to avoid eye-bleach and burning
np.write()
If you want to see how insane fast the pico can be, set sleep to zero.
Current glitch: Sometimes the shell freezes after execution, just power cycle.
Going back to the Buspirate firmware:
- Download the latest firmware version here:
https://forum.buspirate.com/t/bus-pirate-5-auto-build-main-branch/20 - Scroll all the way down to get the latest version.
- Unzip it.
- You will find two uf2 version for Buspirate revisions. Make sure you choose the right one.
- Power-cycle the Buspirate keeping the rear side button pressed.
- A flash-drive appears on the computer, named RPI-RP2. Open it and copy the uf2 file into it.
- Do not unplug, flashing will take place automatically directly after the file transfer was performed (takes about 5 seconds).
- LEDs and display should turn on (if not, now is time to panic).
- Congrats you are back on the original Buspirate firmware.
Well, that’s it. As usual, I’m not responsible for bricked units or otherwise inflicted damage,
