Implementing timers...

A project log for rhombus

An open-source minimalist 68020 based single board computer

jason-westerveltJason Westervelt 12/20/2015 at 09:260 Comments

I have configured the MC68901 TimerA and it is driving the _IRQ line low. The logic analyzer output shows the results of enabling the timer after configuring the interrupt registers...

The _IRQ line is tied to _IPL2 on the 68020 along with a 3K pull-up resistor. _IPL0 and _IPL1 are pulled high. Not even getting _IPEND on the CPU to go low. Think it's time to double-check the interrupt mask, LOL. I'm going to feel stupid if this is the only thing holding me up.