guy
Joined: 21 Oct 2005
Posts: 297
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| another WS2812 library |
 Posted: Mon Jul 06, 2015 2:34 am |
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My code uses the UART to output the time-critical waveforms required to control WS2812 LEDs. It will not work on any PIC since it requires:
* INVERTED UART OUTPUT (could also be done in hardware)
* 64 MHz clock (should also work on 32MHz, not tested)
Here is an example of the waveform:
Here is the code for the library with a small demo.
| Code: |
#include <18LF46K22.h>
#fuses INTRC_IO,NOPROTECT,NOPLLEN,NOBROWNOUT,NOLVP,NOWDT
#use delay(clock=64000000)
#use rs232(stream=LED_STREAM, baud=8000000, xmit=PIN_C6, rcv=PIN_C7,bits=8,parity=N,stop=0,ERRORS,INVERT)
#define NUM_LEDS 24
#define HI_BIT 192 // 0b11000000
#define LOW_BIT 252 // 0b11111100
//==========global variables:===========
byte grn [NUM_LEDS];
byte blu [NUM_LEDS];
byte red [NUM_LEDS];
///////////////////////////////////////////////
#INLINE
void SendByte (byte b) {
byte i;
// send 8 bits, MSB first.
// for each bit send a CHAR that creates the bit's waveform
for(i=0;i<8;i++) {
if(bit_test(b,7)) fputc(HI_BIT,LED_STREAM);
else fputc(LOW_BIT,LED_STREAM);
b<<=1;
}
}
////////////////////////////////////
void Draw (){
unsigned int8 i;
// send all data to LEDs
// data order to transmit is G,R,B, 8 bits each.
for (i=0;i<NUM_LEDS;i++){
SendByte(grn[i]);
SendByte(red[i]);
SendByte(blu[i]);
}
}
/////////////////////////////////////
void initArray() {
byte i;
// assuming 24 LEDs:
for(i=0;i<NUM_LEDS;i++) {
// red channel:
if(i<6) red[i]=i*51;
else if(i<12) red[i]=(11-i)*51;
else red[i]=0;
// grn channel:
if(i<8) grn[i]=0;
else if(i<14) grn[i]=(i-8)*51;
else if(i<20) grn[i]=(19-i)*51;
else grn[i]=0;
// blu channel:
if(i<4) blu[i]=(3-i)*51;
else if(i<16) blu[i]=0;
else if(i<22) blu[i]=(i-16)*51;
else blu[i]=(27-i)*51;
}
}
///////////////////////////////////////
void Rotate() {
byte r,g,b,i;
// rotate colors in array. This is only for demo.
r=red[0];
g=grn[0];
b=blu[0];
for(i=1;i<NUM_LEDS;i++) {
red[i-1]=red[i];
grn[i-1]=grn[i];
blu[i-1]=blu[i];
}
red[NUM_LEDS-1]=r;
grn[NUM_LEDS-1]=g;
blu[NUM_LEDS-1]=b;
}
////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////
void main(){
setup_oscillator(OSC_64MHZ);
initArray();
delay_ms(100);
while(true){
Draw();
delay_ms(60);
Rotate();
}
}
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