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[HP 71B] Software for FRAM71 users
02-05-2017, 07:31 PM (This post was last modified: 02-05-2017 07:33 PM by dayd.)
Post: #25
RE: [HP 71B] Software for FRAM71 users
Hi Dave,

(02-05-2017 01:58 AM)Dave Frederickson Wrote:  So from reading the HP Journal article what do we know?
1. RAM is configured first with the largest blocks first
2. ROM/IRAM is configured second
2.a 32k byte chips are configured down from the highest valid address
2.b.16k byte chips are configured in the remaining space. Observation would indicate up from the next higher valid address from the end of RAM.
3. Devices are configured at addresses that are an even multiple of the Chip size.
  1. RAM devices are configured in order by chip size (not device) then port.
    Size of device = size of internal chips * number of chips
    The buffer contains coded chips’ size and their number, not device size.
    HP-IL ROM device appears in the configuration buffer as one 16k chip.
    FRAM71 devices appeared as one chip per F.Block (a 64k module as 2x32k, a 16k as 1x16k chips)
  2. a- 32k and higher, in higher address multiple of chip (not device) size.
    b- I observed the same behavior as you did

    So far you probably agree and are well aware of those details, I’m just trying to be specific.
  3. Even multiple? Where’s that came from? That would mean that a 1x32k device couldn’t be configured at 40000 but could be at 30000 or 50000.
    Maybe I get confuse by English Language and you mean equal, probably… sorry.

(02-05-2017 01:58 AM)Dave Frederickson Wrote:  From the FRAM71 manual, FRAM71 uses 32k chips so both 64k device and 16k devices will be configured at an even 32k address.

As I didn’t had seen neither found such a statement in the manual and the buffer indicates 1x16k for FRAM 16k devices not 1/2x32k, I conducted some experiments to see how configuration routines attributes 16k or less chips in its third phase.
If what if found is correct, we can all forget about IDS chapter 2.4 description detail “The scheme of where each memory device is configured is fairly complex” because the last(?) piece of the puzzle is pretty simple:

RAM and ROM/IRAM can’t be mixed in the same 32k boundaries;

which means that the first (lower) ROM/IRAM address will always be type “X0000”.
That explain your Warning and why at Educalc they thought that the HP-IL needed 32k.
In my experiment I tried to push the HP-IL ROM in to an “X8000” address, well, I got a Warning and lost HP-IL ROM. When it got back after reconfiguration, it seemed to not have lost the buffer though, HP-IL parameters where still there.
I did that with HC ROM configured without its SC, so I still have to see how system behaves in the F0000 range but as there is no device that I know of under 4k, I can assume that the last 3K of available address space are lost.

regards, André
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[HP 71B] Software for FRAM71 users - dayd - 02-01-2017, 10:17 PM
RE: [HP 71B] Software for FRAM71 users - dayd - 02-05-2017 07:31 PM

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