diff options
Diffstat (limited to 'drivers/led/apa102.c')
| -rw-r--r-- | drivers/led/apa102.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/led/apa102.c b/drivers/led/apa102.c new file mode 100644 index 0000000000..7396dc3c55 --- /dev/null +++ b/drivers/led/apa102.c @@ -0,0 +1,151 @@ +/* Copyright 2020 Aldehir Rojas + * Copyright 2017 Mikkel (Duckle29) + * + * 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 "apa102.h" +#include "quantum.h" + +#ifndef APA102_NOPS +# if defined(__AVR__) +# define APA102_NOPS 0 // AVR at 16 MHz already spends 62.5 ns per clock, so no extra delay is needed +# elif defined(PROTOCOL_CHIBIOS) + +# include "hal.h" +# if defined(STM32F0XX) || defined(STM32F1XX) || defined(STM32F3XX) || defined(STM32F4XX) || defined(STM32L0XX) +# define APA102_NOPS (100 / (1000000000L / (STM32_SYSCLK / 4))) // This calculates how many loops of 4 nops to run to delay 100 ns +# else +# error("APA102_NOPS configuration required") +# define APA102_NOPS 0 // this just pleases the compile so the above error is easier to spot +# endif +# endif +#endif + +#define io_wait \ + do { \ + for (int i = 0; i < APA102_NOPS; i++) { \ + __asm__ volatile("nop\n\t" \ + "nop\n\t" \ + "nop\n\t" \ + "nop\n\t"); \ + } \ + } while (0) + +#define APA102_SEND_BIT(byte, bit) \ + do { \ + writePin(RGB_DI_PIN, (byte >> bit) & 1); \ + io_wait; \ + writePinHigh(RGB_CI_PIN); \ + io_wait; \ + writePinLow(RGB_CI_PIN); \ + io_wait; \ + } while (0) + +uint8_t apa102_led_brightness = APA102_DEFAULT_BRIGHTNESS; + +void static apa102_start_frame(void); +void static apa102_end_frame(uint16_t num_leds); + +void static apa102_send_frame(uint8_t red, uint8_t green, uint8_t blue, uint8_t brightness); +void static apa102_send_byte(uint8_t byte); + +void apa102_setleds(LED_TYPE *start_led, uint16_t num_leds) { + LED_TYPE *end = start_led + num_leds; + + apa102_start_frame(); + for (LED_TYPE *led = start_led; led < end; led++) { + apa102_send_frame(led->r, led->g, led->b, apa102_led_brightness); + } + apa102_end_frame(num_leds); +} + +// Overwrite the default rgblight_call_driver to use apa102 driver +void rgblight_call_driver(LED_TYPE *start_led, uint8_t num_leds) { apa102_setleds(start_led, num_leds); } + +void static apa102_init(void) { + setPinOutput(RGB_DI_PIN); + setPinOutput(RGB_CI_PIN); + + writePinLow(RGB_DI_PIN); + writePinLow(RGB_CI_PIN); +} + +void apa102_set_brightness(uint8_t brightness) { + if (brightness > APA102_MAX_BRIGHTNESS) { + apa102_led_brightness = APA102_MAX_BRIGHTNESS; + } else if (brightness < 0) { + apa102_led_brightness = 0; + } else { + apa102_led_brightness = brightness; + } +} + +void static apa102_send_frame(uint8_t red, uint8_t green, uint8_t blue, uint8_t brightness) { + apa102_send_byte(0b11100000 | brightness); + apa102_send_byte(blue); + apa102_send_byte(green); + apa102_send_byte(red); +} + +void static apa102_start_frame(void) { + apa102_init(); + for (uint16_t i = 0; i < 4; i++) { + apa102_send_byte(0); + } +} + +void static apa102_end_frame(uint16_t num_leds) { + // This function has been taken from: https://github.com/pololu/apa102-arduino/blob/master/APA102.h + // and adapted. The code is MIT licensed. I think thats compatible? + // + // The data stream seen by the last LED in the chain will be delayed by + // (count - 1) clock edges, because each LED before it inverts the clock + // line and delays the data by one clock edge. Therefore, to make sure + // the last LED actually receives the data we wrote, the number of extra + // edges we send at the end of the frame must be at least (count - 1). + // + // Assuming we only want to send these edges in groups of size K, the + // C/C++ expression for the minimum number of groups to send is: + // + // ((count - 1) + (K - 1)) / K + // + // The C/C++ expression above is just (count - 1) divided by K, + // rounded up to the nearest whole number if there is a remainder. + // + // We set K to 16 and use the formula above as the number of frame-end + // bytes to transfer. Each byte has 16 clock edges. + // + // We are ignoring the specification for the end frame in the APA102 + // datasheet, which says to send 0xFF four times, because it does not work + // when you have 66 LEDs or more, and also it results in unwanted white + // pixels if you try to update fewer LEDs than are on your LED strip. + uint16_t iterations = (num_leds + 14) / 16; + for (uint16_t i = 0; i < iterations; i++) { + apa102_send_byte(0); + } + + apa102_init(); +} + +void static apa102_send_byte(uint8_t byte) { + APA102_SEND_BIT(byte, 7); + APA102_SEND_BIT(byte, 6); + APA102_SEND_BIT(byte, 5); + APA102_SEND_BIT(byte, 4); + APA102_SEND_BIT(byte, 3); + APA102_SEND_BIT(byte, 2); + APA102_SEND_BIT(byte, 1); + APA102_SEND_BIT(byte, 0); +} |