MediaWiki:Sitenotice:
2025-12-29: I have restored the wiki to a backup from the end of November. Starting in September 2025, accesses went form the 800MB-1.2GB range per month to 26GB in September, 42GB in October, and 70GB in November with most accesses originating from China. As soon as I realized what was causing all the access problems in November, I shut it down (it had reached 36GB by then) behind a password/login screen. The database had gotten corrupted, and I tried a restore from just before the spike in access but that didn't work. Thus, end of November. I still have the other daily backups so if there were any important additions in December, let me know and maybe they can be recovered. - Allen H.
External Hardware IO Address Map
External Hardware IO Address Map
Tandy designated IO addresses from $FF60 to $FF7F for add-on hardware, but several parties chose to build in the $FF40-$FF5F and $FF80-FF8F ranges as well. Here are known IO addresses for add-on hardware.
- FF40-FF4B Floppy Disk Controllers. See Hardware#Floppy_Disk_Controllers for list.
- FF40-FF4B MEGA mini MPI Serial UART A (gated via $FF7F)
- FF40-FF45 MEGA mini MPI Extended MPI Features (gated via $FF7F)
- FF40-FF41 Game Master Cart
- FF40-FF7F FHL Eliminator Dual Serial Ports (exact 8 byte range selected with jumpers, FF60-FF67 standard)
- FF40-FF7F FHL Eliminator HCA, RTC, Printer Port (exact 8 byte range selected with jumpers, FF70-FF77 standard)
- FF41-FF42 Becker Port used by CoCo3FPGA and some emulators for DriveWire access
- FF4C-FF4F Some third party Floppy Disk Controlers: Sardis, JFD, Disto Super Disk Controller, and Disto Super Disk Controller II
- FF50-FF5F Glenside IDE Controller (first jumper option)
- FF50-FF54 MEGA mini MPI YMF-262 sound generator (gated via $FF7F)
- FF50-FF57 Disto Super Disk Controller
- FF50-FF59 Cloud-9 SuperIDE Interface Default Address Range, modified with jumpers
- FF50-FF5F Disto Super Disk Controller II
- FF50-FF5B MEGA mini MPI Serial UART B (gated via $FF7F)
- FF5A-FF5F CoCo PSG
- FF59 Cloud-9 miniFLASH default address, modified with jumpers
- FF60-FF62 X-Pad Model GT-116
- FF64-FF67 Retro Innovations CoCoFLASH
- FF68-FF6B Deluxe RS232 Pak
- FF68-FF6B CoCo USB Serial Cartridge (default address, modified with dip switches)
- FF68-FF6B CoCoIO (first jumper option)
- FF6C-FF6F Direct Connect Modem Pak
- FF6E-FF6F MIDI Maestro
- FF70-FF7F Glenside IDE Controller (second jumper option)
- FF70-FF73 Am9511 Arithmetic Processor Unit Pak (default address, modified with dip switches)
- FF74-FF75 Cloud-9 TC^3 SCSI Interface default settings, modified with jumpers
- FF74-FF77 Disto Super Disk Controller II
- FF7A-FF7B Orchestra-90 CC (26-3143)
- FF78-FF7B CocoIO (second jumper option)
- FF78-FF79 & FF7C Cloud-9 SuperIDE Interface Real Time Clock
- FF7D-FF7E Speech/Sound Cartridge (26-3144A)
- FF7F Multi-Pak Slot Selection Register
- FF80-FF84 Speech Systems Super Voice
- FF86-FF87 CoCo USB Host (default address, modified with dip switches)
- FFE0-FFE9 & FFEF GIME-X for CoCo 3
Note some devices overlap each other; these devices will conflict and cannot be used together without modification.
Built-in IO devices (such as the PIAs ($FF00-FF3F), CoCo3 GIME ($FF90-FFBF), and SAM ($FFC0-FFDF)) also take the IO space. The 6809/6309 CPU uses $FFF0-FFFF for interrupt vectors.