Can I use a different BIOS chip with the same pinout?

Question

So I have a motherboard (M7VKB) and it has a PMC Chips Pm29F002 flash chip in it. I have another flash chip, an Intel 28F010. The Intel 28F010's pinout is the same as the one in the mobo (except for the addition of Vpp 12V for programming, and the lack of A17 because it is 128K instead of 256K). Do you think I could use it in the motherboard? (assuming I have a custom BIOS that fits in 128K instead of 256K)

---- From here on, not important:

I can't think of anything that would stop me from using the chip, maybe timing, voltage shouldn't be a problem, I think. I have the motherboard, so maybe I should try instead of bothering people on stack overflow but I want to avoid in/out cycles to not wear out the DIP-32 socket on the motherboard and don't really want to brick it by accident at the moment (haven't tried everything in DOS yet, have yet to dump the current BIOS).

not important: The problem I have with this Pm29F002 flash chip is that it has a feature, bootblock write protection. The datasheet gives you instructions on how to enable write protection on the bootblock, but for unlocking write protection it just says "Contact manufacturer for the code to unlock" or something stupid like that. My goal is to attempt to write a custom BIOS for this motherboard, so I need a flash chip that will support me :P. However, I haven't checked the flag that says if the bootblock write protection is actually turned on or not. What really bothers me though is that if I turn on bootblock write protection, I don't know how to disable it. So this PMC chip is stupid.

Answer 1

The Pm29F002 and 28F010 seem to be pin-compatible (except for A17 and the Vpp pin), so that should work.

According to the datasheets that I found, the Pm29F002 has shorter access times than the 28F010. The Pm29F002 comes in 55, 70 and 90ns variants, whereas 28F010 comes in 90, 120 and 150ns variants.

This might be a problem if your motherboard uses short access times.

You can check the number on the Pm29F002 to see which variant you have. It is Pm29F002 followed by T or B and then the time in ns (55, 70 or 90).

Same for the 28F010. It is 28F010 followed by the time in ns (90, 120 or 150).

If you have a programmer that takes the Intel 28F010 and you also have the custom BIOS, you can always give it a try.

You could also use the 28F020 instead, it is the 256kB version and should take the standard M7VKB BIOS unchanged, so you can easily test that it works before you flash it with the custom BIOS.

You can download the BIOS from the BioStar website.