I have a
65C02S processor wired up and the address and data pins connected to an Arduino Mega so that I can print the state of the data bus and address bus for testing purposes. The
65C02 datasheet states that the
RESB input should be held low for 2 clock cycles to initialize the microprocessor and start program execution. As part of the reset, the processor goes through an initialization sequence lasting seven clock cycles. Upon completion of the reset sequence, the program counter is loaded with the reset vector from locations
FFFC (low byte) and
FFFD (high byte). This is the start location for program control.
I expect to see these two addresses on the address bus after I have advanced the processor through its 7 clock cycles, but I don't see them. My question is: do the data pins (D0-D7) need to supply the processor with an instruction during the reset sequence to ensure that the processor puts the address of the reset vector on the address bus, or is the processor kaput? At the moment, the data pins are connected to the Arduino which is only reading the state of the pins.