cardiograph-computer/2023-08-09.md

Dev notes — 2023-08-07

Keypad

An actual hexadecimal layout:

0 1 2 3
4 5 6 7
8 9 A B
C D E F

Another:

1 2 3 A
4 5 6 B
7 8 9 C
0 F E D

The conventional layout for cheap hardware:

1 2 3 A
4 5 6 B
7 8 9 C
* 0 # D

Kim-1:

    GO  ST  RS
AD  DA  PC  +
C   D   E   F
8   9   A   B
4   5   6   7
0   1   2   3

COSMAC VIP/CHIP-8:

1 2 3 C
4 5 6 D
7 8 9 E
A 0 B F

CHIP-8 to QWERTY mapping:

1 2 3 4
Q W E R
A S D F
Z X C V

Turtle graphics

• yesterday Elizabeth had the great idea to create a turtle robot to go with the paper computer
• a minimal LOGO would be a fantastic (if challenging) program to write for the computer
  • it could use the hex keypad:
    • using CHIP-8 layout...
    • A key: mode toggle
    • mode 1: numeric
    • mode 2: commands (tokens?)... something like this:
      • F - mode toggle
      • 2 - forward
      • 4 - left
      • 6 - right
      • 0 - reverse
      • 5 - turn
      • 1 - pen up
      • C - pen down

Dot-matrix display

• Maybe try 5x5, like the micro:bit?