Raspberry PI Pico(W) - 6502 microprocessor clock/timer emulator

An interactive clock/timer emulator for the 6502 microprocessor using repeating timer and pulse width modulation. This emulator can generate clock signals from 1Hz to 125MHz.

Requirements

• ARM toolchain
• GCC
• CMake
• Raspberry PI Pico SDK

GPIO Assignments

• GPIO 16 - Pulse PIN for LEDs
• GPIO 17 - Clock PIN for 6502

Building and Flashing

./upload.sh

Make sure that the Pico is in BOOTSEL mode before running the script.

Connecting to the interactive terminal

Connecting to the terminal using minicom:

minicom -b 115200  -D <serial_port>

Once connected, you should see the following prompt:

Pico Clock/Timer Emulator

Sys Clock:              125000000Hz
Out Clock:              1Hz
Timer:                  RPT
Duty Cycle:             50%

Type '?' for help

>>>

Feel free to explore the commands by typing ? and pressing enter. There are two types of clock generation modes:

• RPT - Repeating Timer Mode used to generate clock frequencies from 1Hz to 9Hz
• PWM - Pulse Width Modulation Mode used to generate clock frequencies from 10Hz to 125MHz

Connecting to 6502

• Connect the Clock PIN to the PHI2 pin of the 6502.