2 Copyright 2019,2020 Jun Wako <wakojun@gmail.com>
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 2 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>.
29 #include "ibmpc_usb.h"
33 static void matrix_make(uint8_t code);
34 static void matrix_break(uint8_t code);
36 static int8_t process_cs1(uint8_t code);
37 static int8_t process_cs2(uint8_t code);
38 static int8_t process_cs3(uint8_t code);
41 static uint8_t matrix[MATRIX_ROWS];
42 #define ROW(code) ((code>>3)&0x0F)
43 #define COL(code) (code&0x07)
45 static int16_t read_wait(uint16_t wait_ms)
47 uint16_t start = timer_read();
49 while ((code = ibmpc_host_recv()) == -1 && timer_elapsed(start) < wait_ms);
53 static uint16_t read_keyboard_id(void)
59 //code = ibmpc_host_send(0xF5);
62 code = ibmpc_host_send(0xF2);
63 if (code == -1) { id = 0xFFFF; goto DONE; } // XT or No keyboard
64 if (code != 0xFA) { id = 0xFFFE; goto DONE; } // Broken PS/2?
66 // ID takes 500ms max TechRef [8] 4-41
67 code = read_wait(500);
68 if (code == -1) { id = 0x0000; goto DONE; } // AT
69 id = (code & 0xFF)<<8;
71 // Mouse responds with one-byte 00, this returns 00FF [y] p.14
72 code = read_wait(500);
77 //code = ibmpc_host_send(0xF4);
82 void hook_early_init(void)
88 void matrix_init(void)
92 // initialize matrix state: all keys off
93 for (uint8_t i=0; i < MATRIX_ROWS; i++) matrix[i] = 0x00;
99 * keyboard recognition
101 * 1. Send F2 to get keyboard ID
102 * a. no ACK(FA): XT keyobard
103 * b. ACK but no ID: 84-key AT keyboard CodeSet2
104 * c. ID is AB 83: PS/2 keyboard CodeSet2
105 * d. ID is BF BF: Terminal keyboard CodeSet3
106 * e. error on recv: maybe broken PS/2
108 uint8_t current_protocol = 0;
109 uint16_t keyboard_id = 0x0000;
110 keyboard_kind_t keyboard_kind = NONE;
111 uint8_t matrix_scan(void)
113 // scan code reading states
128 static uint16_t init_time;
132 xprintf("\nERR:%02X\n", ibmpc_error);
134 // when recv error, neither send error nor buffer full
135 if (!(ibmpc_error & (IBMPC_ERR_SEND | IBMPC_ERR_FULL))) {
136 // keyboard init again
143 // clear or process error
144 ibmpc_error = IBMPC_ERR_NONE;
147 // check ISR state debug
148 if (ibmpc_isr_debug) {
149 xprintf("\nISR:%04X\n", ibmpc_isr_debug);
153 // check protocol AT/XT
154 if (ibmpc_protocol != current_protocol) {
155 xprintf("\nPROTO:%02X\n", ibmpc_protocol);
156 current_protocol = ibmpc_protocol;
161 ibmpc_host_disable();
163 xprintf("I%u ", timer_read());
164 keyboard_kind = NONE;
165 keyboard_id = 0x0000;
170 init_time = timer_read();
174 // wait for keyboard to settle after plugin
175 if (timer_elapsed(init_time) > 1000) {
180 ibmpc_host_isr_clear();
182 wait_ms(1); // keyboard can't respond to command without this
184 // SKIDATA-2-DE(and some other keyboards?) stores 'Code Set' setting in nonvlatile memory
185 // and keeps it until receiving reset. Sending reset here may be useful to clear it, perhaps.
186 // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#select-alternate-scan-codesf0
189 if (0xFA == ibmpc_host_send(0xFF)) {
194 xprintf("A%u ", timer_read());
197 // Reset XT-initialize keyboard
198 // XT: hard reset 500ms for IBM XT Type-1 keyboard and clones
199 // XT: soft reset 20ms min(clock Lo)
200 ibmpc_host_disable(); // soft reset: inihibit(clock Lo/Data Hi)
201 IBMPC_RST_LO(); // hard reset: reset pin Lo
203 init_time = timer_read();
204 state = XT_RESET_WAIT;
207 if (timer_elapsed(init_time) > 500) {
208 state = XT_RESET_DONE;
212 IBMPC_RST_HIZ(); // hard reset: reset pin HiZ
213 ibmpc_host_isr_clear();
214 ibmpc_host_enable(); // soft reset: idle(clock Hi/Data Hi)
216 xprintf("X%u ", timer_read());
217 init_time = timer_read();
221 // 1) Read BAT code and ID on keybaord power-up
222 // For example, XT/AT sends 'AA' and Terminal sends 'AA BF BF' after BAT
223 // AT 84-key: POR and BAT can take 900-9900ms according to AT TechRef [8] 4-7
224 // AT 101/102-key: POR and BAT can take 450-2500ms according to AT TechRef [8] 4-39
225 // 2) Read key typed by user or anything after error on protocol or scan code
226 // This can happen in case of keyboard hotswap, unstable hardware, signal integrity problem or bug
228 /* wait until keyboard sends any code without 10000ms timeout
229 if (timer_elapsed(init_time) > 10000) {
233 if (ibmpc_host_recv() != -1) { // wait for AA
234 xprintf("W%u ", timer_read());
235 init_time = timer_read();
240 // NOTE: we can omit to wait BF BF
241 // ID takes 500ms max? TechRef [8] 4-41, though 1ms is enough for 122-key Terminal 6110345
242 if (timer_elapsed(init_time) > 500) {
245 if (ibmpc_host_recv() != -1) { // wait for BF
246 xprintf("W%u ", timer_read());
247 init_time = timer_read();
252 if (timer_elapsed(init_time) > 500) {
255 if (ibmpc_host_recv() != -1) { // wait for BF
256 xprintf("W%u ", timer_read());
261 keyboard_id = read_keyboard_id();
262 xprintf("R%u ", timer_read());
264 if (0x0000 == keyboard_id) { // CodeSet2 AT(IBM PC AT 84-key)
265 keyboard_kind = PC_AT;
266 } else if (0xFFFF == keyboard_id) { // CodeSet1 XT
267 keyboard_kind = PC_XT;
268 } else if (0xFFFE == keyboard_id) { // CodeSet2 PS/2 fails to response?
269 keyboard_kind = PC_AT;
270 } else if (0x00FF == keyboard_id) { // Mouse is not supported
271 xprintf("Mouse: not supported\n");
272 keyboard_kind = NONE;
273 #ifdef G80_2551_SUPPORT
274 } else if (0xAB86 == keyboard_id ||
275 0xAB85 == keyboard_id) { // For G80-2551 and other 122-key terminal
276 // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#ab86
277 // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#ab85
279 if ((0xFA == ibmpc_host_send(0xF0)) &&
280 (0xFA == ibmpc_host_send(0x03))) {
281 // switch to code set 3
282 keyboard_kind = PC_TERMINAL;
284 keyboard_kind = PC_AT;
287 } else if (0xBFB0 == keyboard_id) { // IBM RT Keyboard
288 // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#bfb0
289 // TODO: LED indicator fix
290 //keyboard_kind = PC_TERMINAL_IBM_RT;
291 keyboard_kind = PC_TERMINAL;
292 } else if (0xAB00 == (keyboard_id & 0xFF00)) { // CodeSet2 PS/2
293 keyboard_kind = PC_AT;
294 } else if (0xBF00 == (keyboard_id & 0xFF00)) { // CodeSet3 Terminal
295 keyboard_kind = PC_TERMINAL;
297 keyboard_kind = PC_AT;
300 xprintf("ID:%04X(%d)\n", keyboard_id, keyboard_kind);
305 xprintf("S%u ", timer_read());
306 switch (keyboard_kind) {
310 led_set(host_keyboard_leds());
313 // Set all keys to make/break type
314 ibmpc_host_send(0xF8);
315 // This should not be harmful
316 led_set(host_keyboard_leds());
322 xprintf("L%u ", timer_read());
325 uint16_t code = ibmpc_host_recv();
331 // Keyboard Error/Overrun([3]p.26) or Buffer full
332 // Scan Code Set 1: 0xFF
333 // Scan Code Set 2 and 3: 0x00
334 // Buffer full(IBMPC_ERR_FULL): 0xFF
335 if (code == 0x00 || code == 0xFF) {
336 xprintf("\n!OVERRUN![");
338 // read and ignore data
341 } while ((code = ibmpc_host_recv()) != -1);
350 switch (keyboard_kind) {
352 if (process_cs1(code) == -1) state = INIT;
355 if (process_cs2(code) == -1) state = INIT;
358 if (process_cs3(code) == -1) state = INIT;
372 bool matrix_is_on(uint8_t row, uint8_t col)
374 return (matrix[row] & (1<<col));
378 uint8_t matrix_get_row(uint8_t row)
383 uint8_t matrix_key_count(void)
386 for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
387 count += bitpop(matrix[i]);
394 static void matrix_make(uint8_t code)
396 if (!matrix_is_on(ROW(code), COL(code))) {
397 matrix[ROW(code)] |= 1<<COL(code);
402 static void matrix_break(uint8_t code)
404 if (matrix_is_on(ROW(code), COL(code))) {
405 matrix[ROW(code)] &= ~(1<<COL(code));
409 void matrix_clear(void)
411 for (uint8_t i=0; i < MATRIX_ROWS; i++) matrix[i] = 0x00;
414 void led_set(uint8_t usb_led)
416 // Sending before keyboard recognition may be harmful for XT keyboard
417 if (keyboard_kind == NONE) return;
419 // XT keyobard doesn't support any command and it is harmful perhaps
420 // https://github.com/tmk/tmk_keyboard/issues/635#issuecomment-626993437
421 if (keyboard_kind == PC_XT) return;
423 // It should be safe to send the command to keyboards with AT protocol
424 // - IBM Terminal doesn't support the command and response with 0xFE but it is not harmful.
425 // - Some other Terminals like G80-2551 supports the command.
426 // https://geekhack.org/index.php?topic=103648.msg2894921#msg2894921
428 // TODO: PC_TERMINAL_IBM_RT support
429 uint8_t ibmpc_led = 0;
430 if (usb_led & (1<<USB_LED_SCROLL_LOCK))
431 ibmpc_led |= (1<<IBMPC_LED_SCROLL_LOCK);
432 if (usb_led & (1<<USB_LED_NUM_LOCK))
433 ibmpc_led |= (1<<IBMPC_LED_NUM_LOCK);
434 if (usb_led & (1<<USB_LED_CAPS_LOCK))
435 ibmpc_led |= (1<<IBMPC_LED_CAPS_LOCK);
436 ibmpc_host_set_led(ibmpc_led);
440 /*******************************************************************************
441 * XT: Scan Code Set 1
445 * E0-escaped scan codes are translated into unused range of the matrix.(54-7F)
447 * 01-53: Normal codes used in original XT keyboard
448 * 54-7F: Not used in original XT keyboard
450 * 0 1 2 3 4 5 6 7 8 9 A B C D E F
451 * 50 - - - - * * x x x x * * * * * *
452 * 60 * * * * x x x x x x x x x x x *
453 * 70 x * * x * * x * * x * x * x x *
455 * -: codes existed in original XT keyboard
456 * *: E0-escaped codes translated
457 * x: Non-espcaped codes(Some are not used in real keyboards probably)
459 * Codes assigned in range 54-7F:
461 * 50 - 60 Up* 70 KANAx
462 * 51 - 61 Left* 71 Insert*
463 * 52 - 62 Down* 72 Delete*
464 * 53 - 63 Right* 73 ROx
465 * 54 PrintScr* 64 F13x 74 Home*
466 * 55 Pause* 65 F14x 75 End*
467 * 56 Euro2x 66 F15x 76 F24x
468 * 57 F11x 67 F16x 77 PageUp*
469 * 58 F12x 68 F17x 78 PageDown*
470 * 59 Keypad=x 69 F18x 79 HENKANx
471 * 5A LGUI* 6A F19x 7A RCTL*
472 * 5B RGUI* 6B F20x 7B MUHENKANx
473 * 5C APP* 6C F21x 7C RALT*
474 * 5D Mute* 6D F22x 7D JPYx
475 * 5E Volume Down* 6E F23x 7E Keypad,x
476 * 5F Volume Up* 6F Keypad Enter* 7F Keypad/ *
478 static uint8_t cs1_e0code(uint8_t code) {
480 // Original IBM XT keyboard doesn't use E0-codes probably
481 // Some XT compatilble keyobards need these keys?
482 case 0x37: return 0x54; // Print Screen
483 case 0x46: return 0x55; // Ctrl + Pause
484 case 0x5B: return 0x5A; // Left GUI
485 case 0x5C: return 0x5B; // Right GUI
486 case 0x5D: return 0x5C; // Application
487 case 0x20: return 0x5D; // Mute
488 case 0x2E: return 0x5E; // Volume Down
489 case 0x30: return 0x5F; // Volume Up
490 case 0x48: return 0x60; // Up
491 case 0x4B: return 0x61; // Left
492 case 0x50: return 0x62; // Down
493 case 0x4D: return 0x63; // Right
494 case 0x1C: return 0x6F; // Keypad Enter
495 case 0x52: return 0x71; // Insert
496 case 0x53: return 0x72; // Delete
497 case 0x47: return 0x74; // Home
498 case 0x4F: return 0x75; // End
499 case 0x49: return 0x77; // Page Up
500 case 0x51: return 0x78; // Page Down
501 case 0x1D: return 0x7A; // Right Ctrl
502 case 0x38: return 0x7C; // Right Alt
503 case 0x35: return 0x7F; // Keypad /
505 // Shared matrix cell with other keys
506 case 0x5E: return 0x70; // Power (KANA)
507 case 0x5F: return 0x79; // Sleep (HENKAN)
508 case 0x63: return 0x7B; // Wake (MUHENKAN)
511 xprintf("!CS1_E0_%02X!\n", code);
517 static int8_t process_cs1(uint8_t code)
522 // Pause: E1 1D 45, E1 9D C5 [a] (TODO: test)
541 matrix_break(code & 0x7F);
556 matrix_make(cs1_e0code(code));
558 matrix_break(cs1_e0code(code & 0x7F));
603 /*******************************************************************************
604 * AT, PS/2: Scan Code Set 2
606 * Exceptional Handling
607 * --------------------
608 * Some keys should be handled exceptionally. See [b].
610 * Scan codes are varied or prefix/postfix'd depending on modifier key state.
612 * 1) Insert, Delete, Home, End, PageUp, PageDown, Up, Down, Right, Left
613 * a) when Num Lock is off
614 * modifiers | make | break
615 * ----------+---------------------------+----------------------
616 * Ohter | <make> | <break>
617 * LShift | E0 F0 12 <make> | <break> E0 12
618 * RShift | E0 F0 59 <make> | <break> E0 59
619 * L+RShift | E0 F0 12 E0 F0 59 <make> | <break> E0 59 E0 12
621 * b) when Num Lock is on
622 * modifiers | make | break
623 * ----------+---------------------------+----------------------
624 * Other | E0 12 <make> | <break> E0 F0 12
625 * Shift'd | <make> | <break>
627 * Handling: These prefix/postfix codes are ignored.
631 * modifiers | make | break
632 * ----------+---------------------------+----------------------
633 * Ohter | <make> | <break>
634 * LShift | E0 F0 12 <make> | <break> E0 12
635 * RShift | E0 F0 59 <make> | <break> E0 59
636 * L+RShift | E0 F0 12 E0 F0 59 <make> | <break> E0 59 E0 12
638 * Handling: These prefix/postfix codes are ignored.
642 * modifiers | make | break
643 * ----------+--------------+-----------------------------------
644 * Other | E0 12 E0 7C | E0 F0 7C E0 F0 12
645 * Shift'd | E0 7C | E0 F0 7C
646 * Control'd | E0 7C | E0 F0 7C
649 * Handling: These prefix/postfix codes are ignored, and both scan codes
650 * 'E0 7C' and 84 are seen as PrintScreen.
653 * modifiers | make(no break code)
654 * ----------+--------------------------------------------------
655 * Other | E1 14 77 E1 F0 14 F0 77
656 * Control'd | E0 7E E0 F0 7E
658 * Handling: Both code sequences are treated as a whole.
659 * And we need a ad hoc 'pseudo break code' hack to get the key off
660 * because it has no break code.
663 * 'Hanguel/English'(F1) and 'Hanja'(F2) have no break code. See [a].
664 * These two Korean keys need exceptional handling and are not supported for now.
667 static uint8_t cs2_e0code(uint8_t code) {
669 // E0 prefixed codes translation See [a].
670 case 0x11: return 0x0F; // right alt
671 case 0x14: return 0x17; // right control
672 case 0x1F: return 0x19; // left GUI
673 case 0x27: return 0x1F; // right GUI
674 case 0x2F: return 0x5C; // apps
675 case 0x4A: return 0x60; // keypad /
676 case 0x5A: return 0x62; // keypad enter
677 case 0x69: return 0x27; // end
678 case 0x6B: return 0x53; // cursor left
679 case 0x6C: return 0x2F; // home
680 case 0x70: return 0x39; // insert
681 case 0x71: return 0x37; // delete
682 case 0x72: return 0x3F; // cursor down
683 case 0x74: return 0x47; // cursor right
684 case 0x75: return 0x4F; // cursor up
685 case 0x7A: return 0x56; // page down
686 case 0x7D: return 0x5E; // page up
687 case 0x7C: return 0x7F; // Print Screen
688 case 0x7E: return 0x00; // Control'd Pause
690 case 0x21: return 0x65; // volume down
691 case 0x32: return 0x6E; // volume up
692 case 0x23: return 0x6F; // mute
693 case 0x10: return 0x08; // (WWW search) -> F13
694 case 0x18: return 0x10; // (WWW favourites) -> F14
695 case 0x20: return 0x18; // (WWW refresh) -> F15
696 case 0x28: return 0x20; // (WWW stop) -> F16
697 case 0x30: return 0x28; // (WWW forward) -> F17
698 case 0x38: return 0x30; // (WWW back) -> F18
699 case 0x3A: return 0x38; // (WWW home) -> F19
700 case 0x40: return 0x40; // (my computer) -> F20
701 case 0x48: return 0x48; // (email) -> F21
702 case 0x2B: return 0x50; // (calculator) -> F22
703 case 0x34: return 0x08; // (play/pause) -> F13
704 case 0x3B: return 0x10; // (stop) -> F14
705 case 0x15: return 0x18; // (previous track) -> F15
706 case 0x4D: return 0x20; // (next track) -> F16
707 case 0x50: return 0x28; // (media select) -> F17
708 case 0x5E: return 0x50; // (ACPI wake) -> F22
709 case 0x3F: return 0x57; // (ACPI sleep) -> F23
710 case 0x37: return 0x5F; // (ACPI power) -> F24
712 // https://github.com/tmk/tmk_keyboard/pull/636
713 case 0x03: return 0x18; // Help DEC LK411 -> F15
714 case 0x04: return 0x08; // F13 DEC LK411
715 case 0x0B: return 0x20; // Do DEC LK411 -> F16
716 case 0x0C: return 0x10; // F14 DEC LK411
717 case 0x0D: return 0x19; // LCompose DEC LK411 -> LGUI
718 case 0x79: return 0x6D; // KP- DEC LK411 -> PCMM
719 case 0x83: return 0x28; // F17 DEC LK411
720 default: return (code & 0x7F);
724 static int8_t process_cs2(uint8_t code)
726 // scan code reading states
756 case 0x84: // Alt'd PrintScreen
760 case 0xAA: // Self-test passed
761 case 0xFC: // Self-test failed
762 // reset or plugin-in new keyboard
766 default: // normal key make
772 xprintf("!CS2_INIT!\n");
777 case E0: // E0-Prefixed
779 case 0x12: // to be ignored
780 case 0x59: // to be ignored
789 matrix_make(cs2_e0code(code));
792 xprintf("!CS2_E0!\n");
797 case F0: // Break code
803 case 0x84: // Alt'd PrintScreen
813 xprintf("!CS2_F0!\n");
818 case E0_F0: // Break code of E0-prefixed
820 case 0x12: // to be ignored
821 case 0x59: // to be ignored
827 matrix_break(cs2_e0code(code));
830 xprintf("!CS2_E0_F0!\n");
835 // Pause make: E1 14 77
858 // Pause break: E1 F0 14 F0 77
894 * Terminal: Scan Code Set 3
897 * https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#scan-code-set-3
899 static int8_t process_cs3(uint8_t code)
904 #ifdef G80_2551_SUPPORT
905 // G80-2551 four extra keys around cursor keys
917 case 0x83: // PrintScreen
920 case 0x84: // Keypad *
923 case 0x85: // Muhenkan
929 case 0x87: // Hiragana
932 case 0x8B: // Left GUI
935 case 0x8C: // Right GUI
938 case 0x8D: // Application
941 #ifdef G80_2551_SUPPORT
942 case 0x80: // G80-2551 four extra keys around cursor keys
946 default: // normal key make
950 xprintf("!CS3_READY!\n");
955 case F0: // Break code
957 case 0x83: // PrintScreen
961 case 0x84: // Keypad *
965 case 0x85: // Muhenkan
973 case 0x87: // Hiragana
977 case 0x8B: // Left GUI
981 case 0x8C: // Right GUI
985 case 0x8D: // Application
994 xprintf("!CS3_F0!\n");
999 #ifdef G80_2551_SUPPORT
1001 * G80-2551 terminal keyboard support
1002 * https://deskthority.net/wiki/Cherry_G80-2551
1003 * https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#g80-2551-in-code-set-3
1005 case G80: // G80-2551 four extra keys around cursor keys
1007 case (0x26): // TD= -> JYEN
1010 case (0x25): // page with edge -> NUHS
1013 case (0x16): // two pages -> RO
1016 case (0x1E): // calc -> KANA
1031 case (0x26): // TD= -> JYEN
1034 case (0x25): // page with edge -> NUHS
1037 case (0x16): // two pages -> RO
1040 case (0x1E): // calc -> KANA
1056 * IBM PC Keyboard Protocol Resources:
1058 * [a] Microsoft USB HID to PS/2 Translation Table - Scan Code Set 1 and 2
1059 * http://download.microsoft.com/download/1/6/1/161ba512-40e2-4cc9-843a-923143f3456c/translate.pdf
1061 * [b] Microsoft Keyboard Scan Code Specification - Special rules of Scan Code Set 1 and 2
1062 * http://download.microsoft.com/download/1/6/1/161ba512-40e2-4cc9-843a-923143f3456c/scancode.doc
1064 * [1] PS/2 Reference Manuals - Collection of IBM Personal System/2 documents.
1065 * http://www.mcamafia.de/pdf/pdfref.htm
1067 * [2] Keyboard and Auxiliary Device Controller - Signal Timing and Format
1068 * http://www.mcamafia.de/pdf/ibm_hitrc07.pdf
1070 * [3] Keyboards(101- and 102-key) - Keyboard Layout, Scan Code Set, POR, and Commands.
1071 * http://www.mcamafia.de/pdf/ibm_hitrc11.pdf
1073 * [4] IBM PC XT Keyboard Protocol
1074 * https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-XT-Keyboard-Protocol
1076 * [5] IBM Keyboard Scan Code by John Elliott - 83-key, 84-key, 102-key and 122-key
1077 * https://www.seasip.info/VintagePC/index.html
1079 * [6] IBM 1391406 Keyboard - Scan Code Set 2 of 102-key PS/2 keyboard
1080 * https://www.seasip.info/VintagePC/ibm_1391406.html
1082 * [7] The IBM 6110344 Keyboard - Scan Code Set 3 of 122-key terminal keyboard
1083 * https://www.seasip.info/VintagePC/ibm_6110344.html
1085 * [8] IBM PC AT Technical Reference 1986
1086 * http://bitsavers.org/pdf/ibm/pc/at/6183355_PC_AT_Technical_Reference_Mar86.pdf
1088 * [y] TrackPoint Engineering Specifications for version 3E
1089 * https://web.archive.org/web/20100526161812/http://wwwcssrv.almaden.ibm.com/trackpoint/download.html
1091 * [z] [Soarer's XT/AT/PS2/Terminal to USB converter]
1092 * https://geekhack.org/index.php?topic=17458.0