FCLab@OvGU / NeoPixel

Simple neopixel (WS2812) library, tuned for stm32 (L432) at 80 MHz Should be compatible with any stm32, different clock speed may require timing adjustments in neopixel.c

Dependents:   Nucleo_neopixel_ovgu Nucleo_neopixel_ovgu1 Nucleo_neopixel_ovgu3

Fork of NeoPixel by Ondřej Hruška

neopixel.cpp@1:037882a8e193, 2017-12-11 (annotated)

Committer:
Hinz
Date:
Mon Dec 11 12:54:00 2017 +0000
Revision:
1:037882a8e193
Parent:
0:a81364d9a67b 
ok

Who changed what in which revision?

UserRevisionLine numberNew contents of line
MightyPork 0:a81364d9a67b 1 #include "mbed.h"
MightyPork 0:a81364d9a67b 2 #include "neopixel.h"
MightyPork 0:a81364d9a67b 3
Hinz 1:037882a8e193 4 NeoPixel::NeoPixel(PinName pin, int n) : DigitalOut(pin)
MightyPork 0:a81364d9a67b 5 {
Hinz 1:037882a8e193 6 _pixels = (Pixel*)malloc(n*sizeof(Pixel));
Hinz 1:037882a8e193 7 memset(_pixels, 0, n*sizeof(Pixel));
Hinz 1:037882a8e193 8 _npixels = n;
MightyPork 0:a81364d9a67b 9 }
MightyPork 0:a81364d9a67b 10
MightyPork 0:a81364d9a67b 11 // The timing should be approximately 800ns/300ns, 300ns/800ns
Hinz 1:037882a8e193 12 void NeoPixel::byte(register uint32_t byte)
MightyPork 0:a81364d9a67b 13 {
MightyPork 0:a81364d9a67b 14 for (int i = 0; i < 8; i++) {
MightyPork 0:a81364d9a67b 15 gpio_write(&gpio, 1);
MightyPork 0:a81364d9a67b 16
MightyPork 0:a81364d9a67b 17 // duty cycle determines bit value
MightyPork 0:a81364d9a67b 18 if (byte & 0x80) {
MightyPork 0:a81364d9a67b 19 // one
MightyPork 0:a81364d9a67b 20 for(int j = 0; j < 6; j++) __nop();
MightyPork 0:a81364d9a67b 21
MightyPork 0:a81364d9a67b 22 gpio_write(&gpio, 0);
MightyPork 0:a81364d9a67b 23 for(int j = 0; j < 2; j++) __nop();
MightyPork 0:a81364d9a67b 24 }
MightyPork 0:a81364d9a67b 25 else {
MightyPork 0:a81364d9a67b 26 // zero
MightyPork 0:a81364d9a67b 27 for(int j = 0; j < 2; j++) __nop();
MightyPork 0:a81364d9a67b 28
MightyPork 0:a81364d9a67b 29 gpio_write(&gpio, 0);
MightyPork 0:a81364d9a67b 30 for(int j = 0; j < 5; j++) __nop();
MightyPork 0:a81364d9a67b 31 }
MightyPork 0:a81364d9a67b 32
MightyPork 0:a81364d9a67b 33 byte = byte << 1; // shift to next bit
MightyPork 0:a81364d9a67b 34 }
MightyPork 0:a81364d9a67b 35
MightyPork 0:a81364d9a67b 36 }
MightyPork 0:a81364d9a67b 37
Hinz 1:037882a8e193 38 void NeoPixel::show(void)
MightyPork 0:a81364d9a67b 39 {
MightyPork 0:a81364d9a67b 40 // Disable interrupts in the critical section
MightyPork 0:a81364d9a67b 41 __disable_irq();
Hinz 1:037882a8e193 42
Hinz 1:037882a8e193 43 for (int i = 0; i < _npixels; i++) {
MightyPork 0:a81364d9a67b 44 // Black magic to fix distorted timing
MightyPork 0:a81364d9a67b 45 #ifdef __HAL_FLASH_INSTRUCTION_CACHE_DISABLE
MightyPork 0:a81364d9a67b 46 __HAL_FLASH_INSTRUCTION_CACHE_DISABLE();
MightyPork 0:a81364d9a67b 47 #endif
MightyPork 0:a81364d9a67b 48
Hinz 1:037882a8e193 49 byte((_pixels+i)->g);
Hinz 1:037882a8e193 50 byte((_pixels+i)->r);
Hinz 1:037882a8e193 51 byte((_pixels+i)->b);
MightyPork 0:a81364d9a67b 52
MightyPork 0:a81364d9a67b 53 #ifdef __HAL_FLASH_INSTRUCTION_CACHE_ENABLE
MightyPork 0:a81364d9a67b 54 __HAL_FLASH_INSTRUCTION_CACHE_ENABLE();
MightyPork 0:a81364d9a67b 55 #endif
MightyPork 0:a81364d9a67b 56 }
MightyPork 0:a81364d9a67b 57
MightyPork 0:a81364d9a67b 58 __enable_irq();
Hinz 1:037882a8e193 59 wait_us(50);
MightyPork 0:a81364d9a67b 60 }
MightyPork 0:a81364d9a67b 61
MightyPork 0:a81364d9a67b 62
Hinz 1:037882a8e193 63 void NeoPixel::setColor(int i, uint32_t color)
MightyPork 0:a81364d9a67b 64 {
Hinz 1:037882a8e193 65 if ((i>=0) && (i<_npixels))
Hinz 1:037882a8e193 66 (_pixels+i)->hex = color;
MightyPork 0:a81364d9a67b 67 }
Hinz 1:037882a8e193 68
Hinz 1:037882a8e193 69
Hinz 1:037882a8e193 70 void NeoPixel::clear(void)
Hinz 1:037882a8e193 71 {
Hinz 1:037882a8e193 72 for (int i=0; i<_npixels; i++)
Hinz 1:037882a8e193 73 (_pixels+i)->hex = 0;
Hinz 1:037882a8e193 74 }