FRAM71B

[Dave Frederickson]

(05-22-2016 08:26 AM)Hans Brueggemann Wrote:  ... consider the case where you hold the DIAG ROM in TOP_FRAM. you may now set the TOP_FRAM config differently. and by setting that config to all zero, you are now able to test "real" modules with the DIAG ROM, without destroying any of the FRAM contents. well, that's at least how it is supposed to work ;o)

Could we not do this using the old scheme?

A few comments:
I recall that changing configuration under program control cause a lot of issues making on-the-fly bank-switching difficult to use. This was implemented for "backup purposes", but since FRAM71 can be backed up using other means it was not needed.

I also recall that the blocks of FRAM that could be swapped under program control could not alter the file chain which limited the feature to the two HC ROM's and empty RAM.

I liked being able to move a single jumper and have the entire personality of the 71 switch. It looks like the FRAM71B will not function like that.

Dave