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HP-71B MultiMod ROM Emulator User Manual
01-20-2021, 02:44 AM (This post was last modified: 01-20-2021 02:45 AM by mfleming.)
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RE: HP-71B MultiMod ROM Emulator User Manual
Hi Sylvain,

Excellent summary! I should include something like this in the Appendix. Here are a couple of comments.

Quote: [*]ROMs
  • ROM order follow chip number in the module (from 0 to 7)
The ROM order of enumeration follows the order of entries in the table. There's also no constraint on the order of chip numbers in the table. So, if you wanted to swap the order of appearance of the MATH and JPC ROMs, just swap the two table entries and change the FLAG value of each. The second entry would have JPC starting at chip 4 (flash block 4) and the third entry would have MATH starting at chip 2 (flash block 2). I was thinking a picture of the mapping between virtual "chips" and physical flash blocks might help.

Quote: [*]ROMs
  • Expected ROM size are: 16KB, 32KB or 64KB
This should really be expected chip size. If you build a ROM from a sequence of 16K chips then it can be any multiple of 16KB. You could build a 48KB ROM from three 16KB chips, or from one 32KB and one 16KB chip if you want!

Quote: [*]ADDR : address of some sort, data is inconsistent, explanation not found in the manual
This is a lookup value used when mapping a 71B address to an address in flash memory. I used to do it by hand but realized it was a certain source of error if others had to do it. The value is now computed when the processor starts.

The table/include format is pretty flexible. If you think in terms of the hardware, chips and such, then it's a bit easier to see what you're doing with the table. Reordering the table for MATH and JPC would be like rewiring the Daisy-In/Daisy-Out signal between chips. The ROMs are still in the same place on the board, you've just moved them around with the wiring order. I hope the manual conveys everything needed to use the MultiMod board. Don't want a whole lot of questions later Smile

Edit: I should warn against changing the MMIO entry. You can probably guess why...

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RE: HP-71B MultiMod ROM Emulator User Manual - mfleming - 01-20-2021 02:44 AM

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