On 11.06.2009 15:12, Morgan Reed wrote:
On Thu, Jun 11, 2009 at 22:51, Carl-Daniel Hailfinger c-d.hailfinger.devel.2006@gmx.net wrote:
Desolder the ID2 pin of the old chip from the board and connect it to VDD (3.3V). Solder the new chip (with the correct BIOS image) on top of the old chip, but connect ID2 of that chip to ground.
I've just done some reading, that should do the trick. Except according to the datasheet you should use ID3 for this not ID2, essentially the ID pins control where in the 8M of space the contents of the chip gets mapped, by using ID3 you can flip your 4M ROM between the top and the bottom of the address range, as I say I've not looked too deeply into LPC but my reading of the datasheet suggests that if you use ID2 you will end up with half of your two ROMs overlapping.
Ah, the common trap of MByte vs. Mbit. The chips are 4 Mbit (512 kByte), so there won't be any overlap. Besides that, the Winbond datasheets explicitly mention that ID3 is not used by the chips unless I'm totally misreading them.
Regards, Carl-Daniel