http://apple2.guidero.us/ 2026-05-04T11:09:02-04:00 http://apple2.guidero.us/ http://apple2.guidero.us/lib/tpl/monochrome/images/favicon.ico text/html 2017-07-25T16:16:39-04:00 http://apple2.guidero.us/doku.php/mg_notes/apple_iic/accelerator?rev=1501013799&do=diff Apple IIc Plus Accelerator The Apple IIc Plus accelerator is essentially a Zip Chip broken out into its discrete components, as Apple licensed the technology from Zip Technologies. All of the registers function exactly like a 4 MHz Zip Chip. Firmware text/html 2017-07-25T16:15:48-04:00 http://apple2.guidero.us/doku.php/mg_notes/apple_iic/firmware_bank_switch?rev=1501013748&do=diff Apple //c and IIc Plus Firmware Banking All Apple //c and IIc Plus computers except ROM $00 ship with two 16K firmware banks, each visible from $C100-$FFFF. The visible bank is switched by a write to $C028. This is not well-documented by the Apple documentation. text/html 2017-11-10T03:46:00-04:00 http://apple2.guidero.us/doku.php/mg_notes/apple_iic/iic_bugs?rev=1510303560&do=diff Apple //c and IIc Plus Firmware Bugs Memory Expansion Firmware The memory expansion firmware has the following code to test the size of the memory expansion card, if installed: numbanks equ $03bb ; screen hole - $c0 sizetemp equ $0478 ; screen hole shared addrl equ $bff8 ; slinky address reg for indirect use addrm equ $bff9 ; real registers are from $c0c0-$c0c3 addrh equ $bffa ; .. data equ $bffb ; slinky data re… text/html 2018-08-01T19:40:12-04:00 http://apple2.guidero.us/doku.php/mg_notes/apple_iic/mig_chip?rev=1533166812&do=diff Apple IIc Plus MIG Chip The MIG is a custom chip in the Apple IIc Plus that provides signals for accessing 3.5" disk drives and access to a 2K static RAM chip mainly used to buffer 3.5" sector data for reading and writing. The RAM is also used for the accelerator. text/html 2018-06-27T20:02:38-04:00 http://apple2.guidero.us/doku.php/mg_notes/apple_iic/secret_iicplus_smartport?rev=1530144158&do=diff Apple IIc Plus Secret Disk II SmartPort In the course of disassembling the Apple IIc Plus firmware, I discovered a secret ProDOS block device and SmartPort implementation for the Disk II. The implementation is complete, including read/write/format, minus a few bogus values in the SmartPort device information. text/html 2017-11-06T22:20:26-04:00 http://apple2.guidero.us/doku.php/mg_notes/apple_iic/start?rev=1510024826&do=diff MG's Apple //c and IIc Plus Tech Notes <ul class="catlist-nslist" ><li class="catlist-page">Apple IIc Plus Accelerator</li><li class="catlist-page">Apple //c and IIc Plus Firmware Banking</li><li class="catlist-page">Apple //c and IIc Plus Firmware Bugs</li><li class="catlist-page">Apple IIc Plus MIG Chip</li><li class="catlist-page">Apple IIc Plus Secret Disk II SmartPort</li></ul> ---------- ​