Yes this is possible and feasible. If you have an onboard serial or parallel port you are not using, you could even leverage those. The serial port can be configured to generate an IRQ when the external device flips the CTS line, and the parallel port can be configured to generate an IRQ when the external device flips the ACK line. You would write a TSR to react to the change and do the setmul. You might need some extra hardware like de-bounce circuit, pull-up or pull-down resistor, and if you want to also use software to turn the turbo LED on and off, a transistor.

It could also be done by building an ISA card with all these components on it and leads for the turbo switch and turbo LED cables.

nice!

serial/parellel port + tsr approach is very interesting ^^ thank you so much for the advice ... i was really having a tricky time finding a starting point for this idea , but now that i know what to look into i should be able to research on my own ^^

i will report back to the forum once/if we start implementing this irl haha

I know you're asking for controlling software by a button, but if it ends up requiring a mess of cables, I'd prefer the Throttle Blaster.

Traditional turbo buttons would usually be implemented with a singular method of slowdown. Whereas tools like SETMUL, CPUSPD, etc, don't just perform a single function, but a plethora of functions to slow down the system.

The first question you need is to figure out what method you want to slow down the system then write a TSR that implements that method. Then create some type of hardware interface (e.g. above mentioned serial/parallel or ISA) to trigger an interrupt request which then be picked up by the TSR to trigger the slowdown.

wbahnassi wrote on Yesterday, 18:11:

I'd prefer the Throttle Blaster.

100% this, https://github.com/scrapcomputing/ThrottleBlaster you get a dial and can tune to your hearts desires and the minimal hardware version (no pcb, just Pico board, encoder, display and a bunch of wires) will cost you a whooping $10