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diff --git a/ADB.txt b/ADB.txt new file mode 100644 index 0000000000..b98cf67610 --- /dev/null +++ b/ADB.txt @@ -0,0 +1,134 @@ +ADB Protocol +============ + +Resources +--------- +Apple IIgs Hardware Reference Second Edition [p80(Chapter6 p121)] + ftp://ftp.apple.asimov.net/pub/apple_II/documentation/Apple%20IIgs%20Hardware%20Reference.pdf +ADB Keycode + http://72.0.193.250/Documentation/macppc/adbkeycodes/ + http://m0115.web.fc2.com/m0115.jpg +ADB Signaling + http://kbdbabel.sourceforge.net/doc/kbd_signaling_pcxt_ps2_adb.pdf +ADB Overview & History + http://en.wikipedia.org/wiki/Apple_Desktop_Bus +Microchip Application Note: ADB device(with code for PIC16C) + http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011062 +AVR ATtiny2131 ADB to PS/2 converter(Japanese) + http://hp.vector.co.jp/authors/VA000177/html/KeyBoardA5DEA5CBA5A2II.html + + +Pinouts +------- + Female socket from the front + + 4o o3 + 2o o1 + == + + 1: Data + 2: Power SW(low when press Power key) + 3: Vcc(5V) + 4: GND + + +Commands +-------- + ADB command is 1byte and consists of 4bit-address, 2bit-command + type and 2bit-register. The commands are always sent by Host. + + Command format: + 7 6 5 4 3 2 1 0 + | | | |------------ address + | |-------- command type + | |---- register + + bits commands + ------------------------------------------------------ + - - - - 0 0 0 0 Send Request(reset all devices) + A A A A 0 0 0 1 Flush(reset a device) + - - - - 0 0 1 0 Reserved + - - - - 0 0 1 1 Reserved + - - - - 0 1 - - Reserved + A A A A 1 0 R R Listen(write to a device) + A A A A 1 1 R R Talk(read from a device) + + The command to read keycodes from keyboard is 0x2C which + consist of keyboard address 2 and Talk against register 0. + + Address: + 2: keyboard + 3: mice + + Registers: + 0: application(keyobard/mice use to store its data.) + 1: application + 2: application + 3: status and command + + +Communication +------------- + This is a minimum information for keyboard communication. + See "Resources" for detail. + + Signaling: + + ~~~~____________~~||||||||||||__~~~~~_~~|||||||||||||||__~~~~ + + |800us | |7 Command 0| | | |15-64 Data 0|Stopbit(0) + +Attention | | | +Startbit(1) + +Startbit(1) | +Tlt(140-260us) + +stopbit(0) + + Bit cells: + + bit0: ______~~~ + 65 :35us + + bit1: ___~~~~~~ + 35 :65us + + bit0 low time: 60-70% of bit cell(42-91us) + bit1 low time: 30-40% of bit cell(21-52us) + bit cell time: 70-130us + [from Apple IIgs Hardware Reference Second Edition] + + Criterion for bit0/1: + After 55us if line is low/high then bit is 0/1. + + Attention & start bit: + Host asserts low in 560-1040us then places start bit(1). + + Tlt(Stop to Start): + Bus stays high in 140-260us then device places start bit(1). + + Global reset: + Host asserts low in 2.8-5.2ms. All devices are forced to reset. + + Send request from device(Srq): + Device can request to send at commad(Global only?) stop bit. + keep low for 300us to request. + + +Keyboard data(register0) + This 16bit data can contains 2 keycodes and 2 released flags. + First keycode is palced in upper nibble. When one keyocode is sent, + lower nibble is 0xFF. + Release flag is 1 when key is released. + + 15 14 . . . . . 8 7 6 . . . . . 0 + | |keycode1 | |keycode2 + |released(1) |released(1) + + Keycodes: + Scancode consists of 7bit keycode and 1bit release flag. + Device can send two keycodes at once. If just one keycode is sent + keycode1 contains it and keyocode2 is 0xFF. + + Power switch: + You can read the state from PSW line(active low) however + the switch has a special scancode 0x7F7F, so you can + also read from Data line. It uses 0xFFFF for release scancode. + +END_OF_ADB |