- /* 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 "gpio.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"
- # include "chibios_config.h"
- # if defined(STM32F0XX) || defined(STM32F1XX) || defined(STM32F3XX) || defined(STM32F4XX) || defined(STM32L0XX) || defined(GD32VF103) || defined(MCU_RP)
- # define APA102_NOPS (100 / (1000000000L / (CPU_CLOCK / 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 { \
- gpio_write_pin(APA102_DI_PIN, (byte >> bit) & 1); \
- io_wait; \
- gpio_write_pin_high(APA102_CI_PIN); \
- io_wait; \
- gpio_write_pin_low(APA102_CI_PIN); \
- io_wait; \
- } while (0)
-
- uint8_t apa102_led_brightness = APA102_DEFAULT_BRIGHTNESS;
-
- static void 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);
- }
-
- static void apa102_start_frame(void) {
- apa102_init();
- for (uint16_t i = 0; i < 4; i++) {
- apa102_send_byte(0);
- }
- }
-
- static void 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();
- }
-
- static void 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 apa102_init(void) {
- gpio_set_pin_output(APA102_DI_PIN);
- gpio_set_pin_output(APA102_CI_PIN);
-
- gpio_write_pin_low(APA102_DI_PIN);
- gpio_write_pin_low(APA102_CI_PIN);
- }
-
- void apa102_setleds(rgb_led_t *start_led, uint16_t num_leds) {
- rgb_led_t *end = start_led + num_leds;
-
- apa102_start_frame();
- for (rgb_led_t *led = start_led; led < end; led++) {
- apa102_send_frame(led->r, led->g, led->b, apa102_led_brightness);
- }
- apa102_end_frame(num_leds);
- }
-
- 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;
- }
- }
|