What is an Apple Language Card and how to use it
Compatible with Apple II and Apple II+ that has a maximum of 48KB of RAM inside an address space of 64KB. Inside this address space, the upper 16KB are divided between I/O (4KB) and ROM (12KB).
The card has an Autostart ROM, which take over Apple’s ROM-F8.
There are three independently things you can control: (1) Write-protect or write-enable RAM of the Language Card; (2) select or deselect RAM read; (3) select first or second 4KB bank of RAM.
|Second 4KB Bank||First 4KB Bank||RAM/ROM selection|
|$C080 [-16256]||$C088 [-16248]||Select RAM, Write-protected RAM|
|$C081 [-16255]||$C089 [-16247]||Deselect RAM read (enable ROM), Two (or more) reads: write enable RAM|
|$C082 [-16254]||$C08A [-16246]||Deselect RAM read (enable ROM), Write-protected RAM|
|$C083 [-16253]||$C08B [-16245]||Select RAM read, Two (or more) reads: write-enable RAM|
From: Apple Language Card: Installation and Operation Manual
REF: Apple Language System manual (pdf) local mirror 20200418