VOGONS

use physical button to control setmul or similar software?

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First post, by nyxf

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hi -

it looks like turbo button stopped being standard after about the 486 cpu series , but for later cpus like '586' / pentium mmx there are some software utilities that can control the cpu's internal registers to achieve a slower speed?

i'm curious if there could be a way to get this later hardware in a case with a turbo button , and rig the button up in a way that it can trigger the software to toggle a slower speed , basically faking an actual turbo button ... mostly curious about what would be the best way to connect an external signal to some kind of software interrupt ... assuming this is a thing that is possible -v-

not sure how feasible this would be but it would be quite fun if possible , so i figured i'd post about it . if there is a way this could work , then me and my friend might start gathering up parts to try and make it. ^^

a main concern of mine is that dos is not multitasking if i remember correctly (?) so it would presumably be difficult to use a button to interrupt it and trigger a background task of sorts ...

i dunno ... are these stupid questions? probably . im not very smart -v-"

Reply 1 of 2, by jakethompson1

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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.

Reply 2 of 2, by nyxf

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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

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