A project to explore ADB(Apple Desktop Bus) protocol for some apple displays.
My end goal is to probably do a DDC to ADB converter, to allow for a better vga connection. At current state its just code to explore and test adb to a display
Most of the registers/addresses that relates to actual monitor settings are only available when the display is turned on. But Some registers like power state, revision, copyright notice, etc. is readable when monitor is turned off.
To read and write settings over ADB, param lrem needs to be set to 0. This is done in the Detect function. It also seems to disable OSD until 1 is written to it again.
At times registers doesnt want to update, usually in certain resolutions. Rebooting the monitor or making it detect a new signal seems to fix it at times.
After writing a register, the display does not save, and previous values will be restored on reboot. This might not be the case for all variables, but most settings variables is. Settings seem to have a save sequence, on Orca and Whaler monitor it seems to be register id/address offset by a certain amount. Im guessing this might be address in rom? For other models im unsure.
DumpSettings1 and DumpSettings2 should dump some pieces of data that is in a parameter file created by service utility.
Default pin in this case is pin 8, as i had issues with pin 3 on an arduino uno. Connected with a pullup resistor as described in other adb projects.
ADB interaction with display is mainly taken from Display Service Utility.
AppleVision/Apple Monitor Plugins binary contains settings information as ladt resources. A script for reading these resources is in dump_settings.py.
This binary contains a bit better way to query monitor type and revision, but is annoying to navigate by its heavy use of components and the ComponentDispatch syscall.
Some notes about automatic white balance and recovery application is notes/
Also contains 2 register dumps (Whaler rev 3)
To reduce space used on the microcontroller, some settings tables been put behind ifdefs (check lib/adb_params/include/Params.h and platformio.ini)
NOTE: This table is not confirmed.
| Codename | Model |
|---|---|
| Telecaster | |
| Sousa | |
| Hammerhead | (AppleVision 1710) |
| Orca | AppleVision 850AV |
| Whaler | AppleVision 850 |
| WarriorEZ | (AppleVision 750) |
| Manta |
macemu/SheepShaverfor dynamic testing of apple adb interactions (Display service utility). AppleVision extension/Monitor plugins extension doesnt work.m68k_mac_reversing_tools
ADB code and project structure is credited to:
- tmk keyboard | adb reading code
- adbuino | adb code and project structure
- stm32-adb2usb | for adb bitfield structure, and gpio setup
- libopencm3-usb-serial | for usb serial code