FRAM71B

[Sylvain Cote]

(10-07-2016 07:10 AM)Erwin Wrote:  An open question is, how do I POKE the possible max RAM afterwards, cause of the different ROM sizes with every bank-switch I have to change it?
Or should I take the minimum RAM when the maximal ROM (per size) are loaded?
How to identify the maximum possible free RAM after bank-switching and does it destroy the mainRAM?

Hello Erwin,

All your questions goes back to memory map and planning.

First thing, you have to understand how memory is allocated and for that, I suggest that you read this great article
Soft Configuration Enhances Flexibility of Handheld Computer Memory by Nathan Meyers

About planning and FRAM71 configuration ...

You could put all you fixed ROM/IRAM modules at the beginning, then the System-RAM and finally two 16/32KB or one 64KB bank switched modules, like this ...

Code:

C#-F#-B# Size Port Type     Description
-------- ---- ---- -------- ---------------------
C0-F3-B0 32KB n/a  HC E0000 41 Translator 
C1-F4-B0 16KB 5.00 SC ROM   41 Translator 
C2-F5-B0 32KB 5.01 SC ROM   Math
C3-F6-B0 32KB 5.02 SC ROM   JPC
C4-F7-B0 32KB 5.03 SC IRAM  Backup
C5-F8-B0 32KB 5.04 SC RAM   Sys RAM 160KB 1 of 5
C6-F9-B0 32KB 5.04 SC RAM   Sys RAM 160KB 2 of 5
C7-FA-B0 32KB 5.04 SC RAM   Sys RAM 160KB 3 of 5
C8-FB-B0 32KB 5.04 SC RAM   Sys RAM 160KB 4 of 5
C9-FC-B0 32KB 5.04 SC RAM   Sys RAM 160KB 5 of 5
CA-F?-B? ??KB 5.05 SC ROM   Bank Switched ROM1
CB-F?-B? ??KB 5.06 SC ROM   Bank Switched ROM2

C# -> Chip #
F# -> FRAM Block # (available: D, E, F, 0, 1 on a 512KB FRAM module)
B# -> Virtual Bank # (0, 1, 2, ...)

Sylvain