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qmk_firmware

custom branch of QMK firmware git clone https://anongit.hacktivis.me/git/qmk_firmware.git

kint41.c (2184B)

    

  1. /* Copyright 2020 QMK
  2.  *
  3.  * This program is free software: you can redistribute it and/or modify
  4.  * it under the terms of the GNU General Public License as published by
  5.  * the Free Software Foundation, either version 2 of the License, or
  6.  * (at your option) any later version.
  7.  *
  8.  * This program is distributed in the hope that it will be useful,
  9.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11.  * GNU General Public License for more details.
  12.  *
  13.  * You should have received a copy of the GNU General Public License
  14.  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15.  */
  17. #include "quantum.h"
  19. #define LED_POWER LINE_PIN13
  21. void matrix_init_kb(void) {
  22.     matrix_init_user();
  24.     // Turn on the Teensy 4.x Power LED:
  25.     gpio_set_pin_output(LED_POWER);
  26.     gpio_write_pin_high(LED_POWER);
  27. }
  29. // delay_inline sleeps for |cycles| (e.g. sleeping for F_CPU will sleep 1s).
  30. // delay_inline assumes the cycle counter has already been initialized and
  31. // should not be modified, i.e. it is safe to call during keyboard matrix scan.
  32. //
  33. // ChibiOS enables the cycle counter in chcore_v7m.c:
  34. // https://github.com/ChibiOS/ChibiOS/blob/b63023915c304092acb9f33bbab40f3ec07a7f0e/os/common/ports/ARMCMx/chcore_v7m.c#L263
  35. static void delay_inline(const uint32_t cycles) {
  36.     const uint32_t start = DWT->CYCCNT;
  37.     while ((DWT->CYCCNT - start) < cycles) {
  38.         // busy-loop until time has passed
  39.     }
  40. }
  42. void matrix_output_unselect_delay(uint8_t line, bool key_pressed) {
  43.     // Use the cycle counter to do precise timing in microseconds. The ChibiOS
  44.     // thread sleep functions only allow sleep durations starting at 1 tick, which
  45.     // is 100μs in our configuration.
  47.     // Empirically: e.g. 5μs is not enough, will result in keys that don’t work
  48.     // and ghost key presses. 10μs seems to work well.
  50.     // On some variants of the hardware, 20μs seems to be required. This was found
  51.     // on a combination of KB600LF+stapelberg v2020-06-30+teensy41.
  53.     // 600 cycles at 0.6 cycles/ns == 1μs
  54.     const uint32_t cycles_per_us = 600;
  55.     delay_inline(20 * cycles_per_us);
  56. }