106 Tiny PIC-like MCU

106 : Tiny PIC-like MCU

  • Author: myrtle
  • Description: serially programmed, subset of PIC ISA, MCU
  • GitHub repository
  • Most recent GDS build
  • HDL project
  • Extra docs
  • Clock: 1000 Hz
  • External hardware: A means of shifting in the program (e.g. another microcontroller, USB GPIO interface, etc) is required at startup. Once running, it is standalone.

How it works

Implements a subset of the PIC mid-range ISA (no SFR, no carry, no call/stack), 6 GPRs, 16 program words.

How to test

Program data is shifted in serially. For each program word, shift in {(1 « address), data} (28 bits total) to prog_data and then assert prog_strobe. Once loaded, deassert (bring high), reset and the program should start running. GPR 6 is GPI and GPR 7 is GPO


# Input Output
0 clock gpo0
1 reset gpo1
2 prog_strobe gpo2
3 prog_data gpo3
4 gpi0 gpo4
5 gpi1 gpo5
6 gpi2 gpo6
7 gpi3 gpo7