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Hardware > Accessing Rom

#15023 - slboytoy - Fri Jan 16, 2004 5:34 am

Ok I have a logic analyzer to look at all 32 pinsouts.

When I go to "read" from an address (0xe000000), I don't see that on bus. I know it's multiplexed, but even the higher address bits (A17-A23), are "FF".

Does it know there is no card pluged in, so it doesn't allow to access the address properly?

I just don't understand why I don't see e000000 on the bus...
Any clue what is going on?

#15025 - tepples - Fri Jan 16, 2004 5:36 am

Addresses in 0x08000000-0x0dffffff use the GBA multiplexed bus protocol. Addresses in 0x0e000000-0x0e00ffff use a different, non-multiplexed wire protocol more closely related to the monochrome Game Boy's protocol.
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#15030 - slboytoy - Fri Jan 16, 2004 7:34 am

Thanks so much!! That helped us and it works fine. Thanks again