VOGONS


First post, by EnergyStar

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Can these chips be used interchangeably?

The UM8663AF comes from the Shuttle HOT-433 motherboard

IMG-20220628-233111.jpg

The UM8663BF comes from the GA-5486al rev.2c motherboard

IMG-20220628-233017.jpg

I would like to test the UM8663BF on the Shuttle HOT-433.

Reply 1 of 3, by vstrakh

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Some forums references them as "the same chip". I'd guess the A vs B indicates the silicon revision or the speed grade, but to tell for sure you'd need datasheets, I couldn't google it 🙁

Reply 3 of 3, by mkarcher

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EnergyStar wrote on 2022-06-28, 21:45:
Can these chips be used interchangeably? […]
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Can these chips be used interchangeably?

The UM8663AF comes from the Shuttle HOT-433 motherboard

The UM8663BF comes from the GA-5486al rev.2c motherboard

I would like to test the UM8663BF on the Shuttle HOT-433.

If I remember correctly what I saw when I reverse engineered BIOSes, the A and B chip have different configuration capabilities, with the later B version being more flexible, allowing something like providing COM1 and COM3 onboard with COM2 being provided by an ISA card, whereas the A variant only supports one even-numbered (1/3) and one odd-numbered (2/4) COM port.

On some boards, the BIOS auto-detects whether the A or B variant is installed and adjust the choices availablr in the BIOS setup. Worst case: Some options you can set in the CMOS behave in strange ways if you swap A/B chips and the BIOS is not prepared.