This is an idea that I was thinking about, using something like LTC6904, which is an adjustable oscillator programmable from 1kHz to 68MHz. The idea is to hook this up to a microcontroller and then replace the existing crystal oscillator that is used to clock the main CPU on an arcade PCB, e.g. a 10MHz crystal for clocking a Motorola 68000. In this way, you could adjust the frequency from stock to whatever overclock you want easily, and by adding a 7 segment or OLED display to the microcontroller, you could easily see the current clock speed. Has anyone done something like this?
- Thread starter alamone
- Start date
astro_zombie138
Champion
I wonder if something like this would work for a completely missing oscillator. I have a strikers 2 pcb that is missing it and tracking down a compatible part has been unfriendly.
You mean the 57.27MHz oscillator? For this application it might be better to just use a resistor adjustable oscillator, in which case you just feed it a resistance value that sets the frequency. In this case you can use a potentiometer to dial in the desired frequency, or use a fixed resistor by using the formula provided by the datasheet.
astro_zombie138
Champion
Well shit, I didn't realize I could do that. But yes that's exactly the frequency I as referring to.
DelsArcade
Enthusiast
This reminds me of what Arcade Jason did to his Asteroids PCB. But he manually swapped out the crystal for each test.
View: https://www.youtube.com/watch?v=rxo36JOd2Xo
