FRAM71B

[Dave Frederickson]

It's so nice to see a new enthusiastic F71/B user! Some comments:

Yes, learn how the 71B memory configuration works from the link Sylvain provided and the 71 S/W IDS, Vol. 1, Chapt. 2.

Start using MEMBUF in the F71 Toolkit to examine memory, especially for those max. memory configurations.

I agree with Bob and Sylvain, you've come a long way in a short time. I think you've enough skill to understand the "advanced" bank switching example. Please give it an attempt and provide feedback.

For a whole F71 document I think that's not a bad idea. For now I use a soft copy of the entire [FRAM71] Pre-Production Batch thread.

Maximum Memory Configurations

I explored this a while ago: http://www.hpmuseum.org/forum/thread-4551.html

Two points:
1. The 71B assigns memory chips to 71B memory H-Addresses by size. This explains Note 2 on p.12 of the F71B manual.
Chip-addresses as "seen" by your HP-71B will vary according to the calculator’s
memory configuration routine. For example, if you configure RAM with Chip_0 =
16 KByte and Chip_1 = 32 KByte, they may have their FRAM base addresses at
F_0x30000 and F_x40000, respectively. However, your HP-71B will configure Chip_0
at H_0x40000 and Chip_1 at H_0x30000.

2. The 71B partitions RAM chips first then the ROM's and IRAM's. This can explain a lot of strange behavior.

Here are some questions to ponder:
1. In EduCALC Tech Note #4 it states:
The HP-IL module actually needs 16K, but 32K should be allocated because the HP-71 often configures the system as 32K for HP-IL.

What??? Not exactly true. What is observed is that sometimes when the HP-IL module is installed there's 32K less memory available. Why?

2. On p.16 of the F71B manual there are a couple of examples of maximum memory configurations:
MAX RAM, FORTH
"93 E4 95 96 97 98 99 9A 9B 9C 9D AE …" (93 is HC, E4 is SC ROM for FORTH) = 320 KB RAM
MAX RAM, IL & FORTH
"93 E4 95 96 97 98 99 9A 9B 9C 9D AE …" (93 is HC, E4 is SC ROM for FORTH) = 320 KB RAM

The second configuration yields the same amount of RAM but includes the HP-IL module. Why is this?

3. Sometimes when FREEPORT is executed a configuration warning (Wrn: Configuration) occurs.
http://www.hpmuseum.org/forum/thread-251...l#pid27688
This doesn't change the amount of memory configured. Why the warning?

4. In this post it is pointed out that the maximum amount of memory was achieved by configuring 16K chip as an IRAM: http://www.hpmuseum.org/forum/thread-455...l#pid40891
This will fail if the chip is configured as RAM. Why? This is related to 3.


Any questions?

Dave