Apple-2-HW/micro-sci-a2-controller
1
0
Fork 0
mirror of https://codeberg.org/cryu/micro-sci-a2-controller synced 2024-11-22 01:31:27 +00:00
Code Issues Packages Projects Releases Wiki Activity
63 Commits 4 Branches 2 Tags 54 MiB
Assembly 91%
C 5.6%
Makefile 3.4%
c458ee9cb5
Go to file
Christopher RYU c458ee9cb5 Use CMOS parts where appropriate (verified!)
2023-07-29 17:33:56 +09:00
apple2-bus.pretty Initial commit. 2023-07-10 05:40:39 +09:00
doc Add original user documentation. 2023-07-26 10:22:07 +09:00
firmware Sync. 2023-07-29 06:33:03 +09:00
.gitignore Nuke erroneously added files. 2023-07-29 06:35:24 +09:00
apple2.kicad_sym Initial commit. 2023-07-10 05:40:39 +09:00
eprom.kicad_sym Switch to 2716/2732. 2023-07-16 11:48:36 +09:00
fp-lib-table Initial commit. 2023-07-10 05:40:39 +09:00
LICENSE Initial commit 2023-07-09 20:35:18 +00:00
MicroSci Floppy Controller.kicad_pcb Checkpoint. 2023-07-20 07:07:15 +09:00
MicroSci Floppy Controller.kicad_pro Checkpoint. 2023-07-20 07:07:32 +09:00
MicroSci Floppy Controller.kicad_sch Use CMOS parts where appropriate (verified!) 2023-07-29 17:33:56 +09:00
README.md Add minimal calibration procedure. 2023-07-27 14:17:21 +09:00
sym-lib-table Switch to 2716/2732. 2023-07-16 11:48:36 +09:00
TTL.kicad_sym Initial commit. 2023-07-10 05:40:39 +09:00
usci.png Re-render. 2023-07-20 07:08:23 +09:00

README.md

Micro-SCI / Franklin Apple ][ Floppy Drive Controller

This is a clone of the Micro-SCI / Franklin floppy drive controller.

v0.1 is a direct clone, reverse-engineered from a Micro-SCI board. It was cross-checked with a Franklin-branded board, as well as the (belatedly discovered) official Franklin schematic (included in doc/service_and_schematics.pdf)

v0.2 has the following enhancements over the original design:

  • the 2708 EPROM has been replaced with a more-common 2716/2732 EPROM
  • decoupling capacitors have been added
  • footprints for all capacitors and resistors have been modernized
  • firmware EPROM bank selection jumpers replaced with a DIP switch
  • obsolete MPS-U51 transistor replaced with modern equivalent
  • clearly-marked calibration test points have been added
  • ground pours used to increase operational stability
  • support for using Floppy Emu in dual-drive emulation mode with one cable

Firmware images can be built via the Makefile in the firmware subdirectory. The build framework requires cc65.

usci

EPROM bank select switches (J4)

  • 1:off 2:off - controller test firmware (0x0000)
  • 1:off 2: on - 16-sector firmware (0x0100)
  • 1: on 2:off - 13-sector firmware (0x0200)
  • 1: on 2: on - firmware "put jumpers here" splash screen (0x0300)

Calibration procedure

  • set J4 to off/off ("controller test firmware")
  • connect oscilloscope to TP1
  • start machine
  • execute "call 50688"
  • execute "AAW" (and immediately hit ESC)
  • adjust R1 until waveform period is 5.4 microseconds
  • connect oscilloscope to TP2
  • execute "99W" (and immediately hit ESX)
  • adjust R2 until waveform period is 3.8 microseconds
  • card is now calibrated, power off machine and set J4 to "16-sector firmware"

Construction notes

  • J3 can be omitted if this controller is used with a FloppyEmu