Writing TI-59 mag cards.

[Dave Britten]

Yup, you are correct. See page VII-1 of the manual ("Personal Programming") for a diagram, but here's the breakdown:

Bank 1: steps 0-239 or registers 99-90
Bank 2: steps 240-479 or registers 89-60
Bank 3: steps 480-719 or registers 59-30
Bank 4: steps 720-959 or registers 29-00

The default partitioning at power on has banks 1 and 2 designated as 480 program storage and banks 3 and 4 for 60 registers. Also note that a bank can contain a mix of program steps and storage registers if you've partitioned memory with something other than 0, 30, 60, or 90 registers.

One trick I like to do when writing a program card is to verify it by reading it back into bank 4 (put -4 in the display to force reading the card as bank 4). That way you can verify the card is good without replacing the program steps in the lower banks - or inadvertently blowing them away if the read/write fails! After reading the card this way, hit 2nd CMs to clear the junk data that will be in the storage registers.