qmk-firmware/drivers/avr/apa102.c

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/*
* APA102 lib V1.0a
*
* Controls APA102 RGB-LEDs
* Author: Mikkel (Duckle29 on github)
*
* Dec 22th, 2017 v1.0a Initial Version
*
* 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 <avr/interrupt.h>
#include <avr/io.h>
#include <util/delay.h>
#include "debug.h"
// Setleds for standard RGB
void inline apa102_setleds(LED_TYPE *ledarray, uint16_t leds){
apa102_setleds_pin(ledarray,leds, _BV(RGB_DI_PIN & 0xF), _BV(RGB_CLK_PIN & 0xF));
}
void static inline apa102_setleds_pin(LED_TYPE *ledarray, uint16_t leds, uint8_t pinmask_DI, uint8_t pinmask_CLK){
pinMode(RGB_DI_PIN, PinDirectionOutput);
pinMode(RGB_CLK_PIN, PinDirectionOutput);
apa102_send_array((uint8_t*)ledarray,leds)
}
void apa102_send_array(uint8_t *data, uint16_t leds){ // Data is struct of 3 bytes. RGB - leds is number of leds in data
apa102_start_frame();
while(leds--){
apa102_send_frame(0xFF000000 | (data->b << 16) | (data->g << 8) | data->r);
data++;
}
apa102_end_frame(leds);
}
void apa102_send_frame(uint32_t frame){
for(uint32_t i=0xFF; i>0;){
apa102_send_byte(frame & i);
i = i << 8;
}
}
void apa102_start_frame(){
apa102_send_frame(0);
}
void apa102_end_frame(uint16_t 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?
// We need to send some more bytes to ensure that all the LEDs in the
// chain see their new color and start displaying it.
//
// 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).
// For the APA102C, that is sufficient.
//
// The SK9822 only updates after it sees 32 zero bits followed by one more
// rising edge. To avoid having the update time depend on the color of
// the last LED, we send a dummy 0xFF byte. (Unfortunately, this means
// that partial updates of the beginning of an LED strip are not possible;
// the LED after the last one you are trying to update will be black.)
// After that, to ensure that the last LED in the chain sees 32 zero bits
// and a rising edge, we need to send at least 65 + (count - 1) edges. It
// is sufficent and simpler to just send (5 + count/16) bytes of zeros.
//
// We are ignoring the specification for the end frame in the APA102/SK9822
// datasheets because it does not actually ensure that all the LEDs will
// start displaying their new colors right away.
apa102_send_byte(0xFF);
for (uint16_t i = 0; i < 5 + leds / 16; i++){
apa102_send_byte(0);
}
}
void apa102_send_byte(uint8_t byte){
uint8_t i;
for (i = 0; i < 8; i++){
digitalWrite(RGB_DI_PIN, !!(byte & (1 << (7-i)));
digitalWrite(RGB_CLK_PIN, PinLevelHigh);
}
}