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author | Nick Brassel <nick@tzarc.org> | 2021-08-29 08:20:25 +1000 |
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committer | Nick Brassel <nick@tzarc.org> | 2021-08-29 08:20:25 +1000 |
commit | f061ca497464fe85284906fb163a33eaee7a91ef (patch) | |
tree | 33ef1bfb529aed382e8526c607c4e18717f92571 /keyboards/kinesis/kint41/kint41.c | |
parent | ff65185dec6f97be1eb49f17cea526a0d0bbf3d6 (diff) | |
parent | 4bad375d7c09d949a9dcdd4feba147c9c7a67ec6 (diff) |
Breaking changes develop merge to master, 2021Q3 edition. (#14196)
Diffstat (limited to 'keyboards/kinesis/kint41/kint41.c')
-rw-r--r-- | keyboards/kinesis/kint41/kint41.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/keyboards/kinesis/kint41/kint41.c b/keyboards/kinesis/kint41/kint41.c new file mode 100644 index 0000000000..ab6567d097 --- /dev/null +++ b/keyboards/kinesis/kint41/kint41.c @@ -0,0 +1,52 @@ +/* Copyright 2020 QMK + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include "kint41.h" + +void matrix_init_kb(void) { + matrix_init_user(); + +// Turn on the Teensy 4.x Power LED: +#define LED_POWER LINE_PIN13 + setPinOutput(LED_POWER); + writePinHigh(LED_POWER); +} + +// delay_inline sleeps for |cycles| (e.g. sleeping for F_CPU will sleep 1s). +// delay_inline assumes the cycle counter has already been initialized and +// should not be modified, i.e. it is safe to call during keyboard matrix scan. +// +// ChibiOS enables the cycle counter in chcore_v7m.c: +// https://github.com/ChibiOS/ChibiOS/blob/b63023915c304092acb9f33bbab40f3ec07a7f0e/os/common/ports/ARMCMx/chcore_v7m.c#L263 +static void delay_inline(const uint32_t cycles) { + const uint32_t start = DWT->CYCCNT; + while ((DWT->CYCCNT - start) < cycles) { + // busy-loop until time has passed + } +} + +void matrix_output_unselect_delay(uint8_t line, bool key_pressed) { + // Use the cycle counter to do precise timing in microseconds. The ChibiOS + // thread sleep functions only allow sleep durations starting at 1 tick, which + // is 100μs in our configuration. + + // Empirically: e.g. 5μs is not enough, will result in keys that don’t work + // and ghost key presses. 10μs seems to work well. + + // 600 cycles at 0.6 cycles/ns == 1μs + const uint32_t cycles_per_us = 600; + delay_inline(10 * cycles_per_us); +} |