Running the robot with MMBasic

PicoMite MMBasic

MMBasic is an implementation of Microsoft BASIC, which runs directly on a selection of microcontrollers, including the Raspberry Pi Pico featuring the rp2040 chip. The MMBasic interpreter was created by Geoff Graham; for the full story and detailed information on supported hardware see his website. The "PicoMite" is a Raspberry Pi Pico running an MMBasic version implemented by Geoff Graham and Peter Mather.

MMBasic allows direcly accessing the microcontroller's hardware, supports many communication protocols, contains drivers for displays and SD cards, and is surprisingly fast. MMBasic features a built-in editor with syntax-highlighting, which means all one needs to program is a terminal program, such as TeraTerm. The PicoMite firmware is open source and supported by an active forum. In addition, an excellent manual is available.

Loading the PicoMite MMBasic firmware

How to load the MMBasic firmware onto the Pico is described in the manual. Therefore, here only a few hints that I found useful:

• Before loading the PicoMite onto a microcontroller that contains a different firmware (e.g. MicroPython), it can be useful to first "nuke" the controller, meaning to reset the flash completely.
• When the MMBasic firmware is already installed: Instead of using the BOOTSEL button, simply entering update firmware brings up the RPI-RP2 drive and a new version of the MMBasic firmware can be uploaded.

  Note that this also deletes all files on in the flash! Before updating, always make sure that you have a backup of your code!

• For completeness sake, how to build the PicoMite MMBasic firmware from the Peter Mather's repository, is explained here. But there is currently no need for that except maybe curiosity.

Uploading the code

As described in the PicoMite Manual I recommend TeraTerm to interact with MMBasic on the Pico. To transfer one of the the demo programms to the Pico, type xmodem receive into the terminal, and then transfer the program from the PC via TeraTerm's menu (File/Transfer/XMODEM/Send). To save programs on the PC, type xmodem send and use File/Transfer/XMODEM/Receive.