Adafruit converted an earlier iteration back in December, 2016 using an ATmega1284 microcontroller. For this build:
It’s a special version of my uLisp interpreter for ARM boards, designed to run on an Adafruit ItsyBitsy M0, or an ATSAMD21E on a prototyping board, interfaced to an I2C OLED display.
The Lisp workspace is displayed on a 64×48 OLED display. This is an ideal fit, as uLisp running on an ATSAMD21 gives you a workspace of 3072 free Lisp objects (each of 8 bytes), and the 64×48 display provides 3072 pixels. I chose a low-cost monochrome I2C display. The program would also work on larger SSD1306-based OLED displays, such as the widely available 128×64 ones.
Free Lisp objects are displayed in black, and when an object is in use it is displayed in white. Periodically you see the garbage collection reclaiming used objects that can no longer be accessed.
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