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); +} | 
