clock jumpers on early 386 boards \ VOGONS

clock jumpers on early 386 boards

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First post, by noshutdown

Posted on 2024-08-19, 02:55

noshutdown Offline

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we know that most early 386 boards had single-frequency crystals, rather than adjustable clockgens.
however, some 386 boards with crystal still have clock jumpers on them.
do they have extra circuit to change the clock generated from crystal, or just sets the clock message that displayed by bios without actually changing speed?

Reply 1 of 1, by Grzyb

Posted on 2024-08-19, 04:03

Grzyb Offline

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Any example of such a board?

I suspect such boards were designed to accomodate various CPUs - with various crystals, of course.
ISA, however, should always work at 8 MHz, therefore the jumpers to select CPU/ISA clock divisor.

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