implement front panel

[nczempin]

1. debounce buttons: #16
2. toggle run vs halt
3. READ
4. WRITE/LOAD
5. LOAD/WRITE

[nczempin]

the reference TM-16 has:

• 16 switches
• 16 LEDs
• one rotary switch with RUN/READ/WRITE/LOAD
• one debounced push button

On the Basys3 board, I have:

• 16 switches
• 16 LEDs
• four seven-segment displays (could be used as a 16 bit hex display, with 4 decimal points for other purposes)
• five push buttons

a bunch of GPIO lines:

• 4x8 GPIO pins
• VGA
• (not going to count#) USB

[nczempin]

A rotary switch would have to be implemented off-board, so for now I'll use a different scheme to implement the functionality behind the rotary switch plus push button:

• the four possible states will be displayed using 2 of the 4 decimal points on the sseg display.
• one push button will be used to cycle through these states
• another push button will be used as the original push button

Then I'll have two more dp to use as status LEDs (for now I'll use fetch and execute), as well as 16 bits of hex display. For now I'll just duplicate the 16 LEDs.

For the three remaining buttons I could implement some way to cycle through what is being displayed on the hex and/or LEDs. It would probably make sense then to use the remaining two dps to indicate that state.

[nczempin]

39

[nczempin]

54

[nczempin]

64