Diff: neopixel.cpp

Revision:

0:ca84ed7518f5

Child:

5:a7894e6982ea

diff -r 000000000000 -r ca84ed7518f5 neopixel.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/neopixel.cpp	Thu Jan 02 09:30:06 2020 +0000
@@ -0,0 +1,104 @@
+#include "mbed.h"
+#include "neopixel.h"
+
+const int wait_time[4][2] = {
+    {6,14},
+    {2, 5},
+    {2, 6},
+    {5,11}
+};
+    
+NeoPixelOut::NeoPixelOut(PinName pin) : DigitalOut(pin)
+{
+    normalize = false;
+    global_scale = 1.0f;
+    #ifdef __STM32L432xx_H
+        boad_ = 0;
+    #endif
+    #ifdef __STM32F446xx_H
+        boad_ = 1;
+    #endif
+}
+
+// The timing should be approximately 800ns/300ns, 300ns/800ns
+void NeoPixelOut::byte(register uint32_t byte)
+{        
+    for (int i = 0; i < 8; i++) {
+        gpio_write(&gpio, 1);
+        
+        // duty cycle determines bit value
+        if (byte & 0x80) {
+            // one
+            for(int j = 0; j < wait_time[0][boad_]; j++) asm("NOP");//6 14
+            
+            gpio_write(&gpio, 0);
+            for(int j = 0; j < wait_time[1][boad_]; j++) asm("NOP");//2 5
+        }
+        else {
+            // zero
+            for(int j = 0; j < wait_time[2][boad_]; j++) asm("NOP");//2 6
+            
+            gpio_write(&gpio, 0);
+            for(int j = 0; j < wait_time[3][boad_]; j++) asm("NOP");//5 11
+        }
+
+        byte = byte << 1; // shift to next bit
+    }
+    
+}
+
+void NeoPixelOut::send(Pixel *colors, uint32_t count, bool flipwait)
+{
+    // Disable interrupts in the critical section
+    __disable_irq();
+
+    Pixel* rgb;
+    float fr,fg,fb;
+    for (int i = 0; i < count; i++) {
+        rgb = colors++;
+        fr = (int)rgb->r;
+        fg = (int)rgb->g;
+        fb = (int)rgb->b;
+        
+        if (normalize) {
+            float scale = 255.0f/(fr+fg+fb);           
+            fr *= scale;
+            fg *= scale;
+            fb *= scale;            
+        }
+        
+        fr *= global_scale;
+        fg *= global_scale;
+        fb *= global_scale;
+        
+        if (fr > 255) fr = 255; 
+        if (fg > 255) fg = 255;
+        if (fb > 255) fb = 255;
+        if (fr < 0) fr = 0; 
+        if (fg < 0) fg = 0;
+        if (fb < 0) fb = 0;
+        
+        // Black magic to fix distorted timing
+        #ifdef __HAL_FLASH_INSTRUCTION_CACHE_DISABLE
+        __HAL_FLASH_INSTRUCTION_CACHE_DISABLE();
+        #endif
+        
+        byte((int)fg);
+        byte((int)fr);
+        byte((int)fb);
+        
+        #ifdef __HAL_FLASH_INSTRUCTION_CACHE_ENABLE
+        __HAL_FLASH_INSTRUCTION_CACHE_ENABLE();
+        #endif
+    }
+
+    __enable_irq();
+
+    if (flipwait) flip();
+}
+
+
+void NeoPixelOut::flip(void)
+{
+    wait_us(50);    
+}