Hi All, Ok I got my ext 80-col card book in the mail today (hooray ebay!) and here's the lowdown on read or write to the switches. Unless it's a "status" switch, you specifically have to write to it. If it's a "status" switch, you have to read from it. For example: RAM WRITE select softswitch: RAMWRT. To switch banks, WRITE to either location $C005 (aux) or $C004 (main) On: Write AUX 48K $C005 Off: Write MAIN 48K $C004 To determine which bank is active, READ from $C014 Read RAMWRT Switch $C014 There's a rather long drawn out assembly listing and a long-drawn out Applesoft basic (data / poke / call) program example for determining if the Apple is a II, a //e, a //e w/ 80 col card, or a //e with 64k 80 col card and if need be, I suppose I could clack it into the computer for the OP to use or base his routine on. Honestly though, for the few bucks plus shippnig, you should score an "extended 80-Column text card supplement" from eBay as it's a virtual minefield in RAM depending on what switches are thrown and what ones are not. Later, Craig -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 In article <8Khpd.1682$VL6.925@clgrps13>, Craig Bower \(Bender MX\) wrote: >"Oliver Schmidt" wrote in message >> 2. How do I detect that an 80 col card is actually installed? Checking >> for the existence of the $C300 firmware seems to be wrong from what I >> understood from your answers. > >Not specifically wrong, I misunderstood your original question! :) > >Look for specific "signature" bytes that are in the $C300 range and are >unique to the 80-column card. From my somewhat limited experimentation >tonight, the old style (BIG) and new style (small) 80-Col / 64K cards >both have the first three bytes as follows: > >C300- 2C 43 CE > >And when I check the same memory location after pulling the cards, >I get the exact same bytes. That happens because the 80-column firmware doesn't reside on the 80-column card. Take a look at what's on the card. An extended 80-column card has eight 64Kx1 DRAM chips (4164 or equivalent), a 3-state octal latch (74LS374), and an octal transceiver (74LS245). Ten bypass capacitors, two resistors, and a two-pin header make up the rest of the parts list. None of those are ROMs. The 80-column firmware in a IIe resides in the motherboard ROMs (more specifically, the CD ROM). As someone else already mentioned, you need to test for the presence of auxiliary memory somewhere in text page 1 to determine if a IIe can display 80-column text. (That's what's on the original extended 80-column card, Apple part number 820-0067-B. Third-party workalikes and Apple's later extended 80-column card that used two 64Kx4 DRAM chips instead of eight 64Kx1s could/will be different.) _/_ / v \ Scott Alfter (remove the obvious to send mail) (IIGS( http://alfter.us/ Top-posting! \_^_/ rm -rf /bin/laden >What's the most annoying thing on Usenet? -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (Linux) iD8DBQFBpkjNVgTKos01OwkRApJqAKCh1lv+BiCyoMj1Q9TPoD8DCTfYIACg3BY6 dAIMQJfELplKH9V42bu7ODs= =4AjB -----END PGP SIGNATURE-----