I have continued working on controlling the WS2812B leds and enhanced the source with a few neat features like draw line, circle and alpha blending.
This code has been tested with a Microchip PIC32MX250F128B micro controller, and XC32 C++ with optimization set to 1
Running this code you should get something like this:
/*
* File: main.cpp
* Author: Henrik Thulin
*
* Created on den 2 may 2014, 02:26
*
* xc32-g++ optimizer should be set to 1
*/
#pragma config POSCMOD=XT
#pragma config FSOSCEN=OFF
#pragma config FNOSC=PRIPLL
#pragma config OSCIOFNC=ON
#pragma config FPLLODIV=DIV_1
#pragma config FPLLMUL=MUL_20
#pragma config FPLLIDIV=DIV_1
#pragma config FWDTEN=OFF
#pragma config FPBDIV=DIV_1
#pragma config CP=OFF
#pragma config BWP=OFF
#pragma config PWP=OFF
#define SYS_FREQ (80000000L)
#define GetPeripheralClock() (FYC/(1 << OSCCONbits.PBDIV))
#define GetInstructionClock() (FYC)
// For 8x8 leds
#define ROWS 8
#define COLS 8
// B5 is here used as output pin
#define LEDPORT IOPORT_B
#define LEDPIN BIT_5
#define LEDHIGH mPORTBSetBits(LEDPIN);
#define LEDLOW mPORTBClearBits(LEDPIN);
#include
#include
unsigned int bitmapBuffer[ROWS*COLS];
// For these timings to be correct, optimization 1 should be used
void sendBitmapPixel(unsigned int x) {
char i = 24;
do {
if ((x >> --i) & 1) {
LEDHIGH
Nop();
Nop();
Nop();
Nop();
Nop();
LEDLOW
} else {
LEDHIGH
Nop();
Nop();
LEDLOW
Nop();
Nop();
Nop();
Nop();
}
} while (i > 0);
}
void sendBitmapBuffer() {
for (int i = 0; i < COLS * ROWS; i++)
sendBitmapPixel(bitmapBuffer[i]);
}
// returns alpha, green, red, blue that'll work with the WS2811, but for simplicity is called ARGB
unsigned int getARGB(unsigned char alpha, unsigned char r, unsigned char g, unsigned char b) {
return (alpha << 24) | (g << 16) | (r << 8) | b;
}
// converts alpha, red, green and blue to alpha, green, red and blue
unsigned int getARGB(unsigned int i) {
return (i & 0xff000000) | ((i & 0x00ff0000) >> 8) | ((i & 0x0000ff00) << 8) | (i & 0x000000ff);
}
unsigned int getPixel(char x, char y) {
return bitmapBuffer[y * COLS + x];
}
unsigned int addAlphaColor(char x, char y, unsigned int add) {
unsigned int original = getPixel(x, y);
float alpha = (float) ((add & 0xff000000) >> 24) / 0xff;
unsigned char green = (((float) ((original >> 16) & 0xff) * (1 - alpha)) + ((float) ((add >> 16) & 0xff) * alpha));
unsigned char red = (((float) ((original >> 8) & 0xff) * (1 - alpha)) + (((float) ((add >> 8) & 0xff)) * alpha));
unsigned char blue = (((float) (original & 0xff) * (1 - alpha)) + ((float) ((add & 0xff) * alpha)));
return (green << 16 | red << 8 | blue);
}
void setPixel(char x, char y, unsigned int color) {
if (x < 0 || y < 0 || x >= COLS || y >= ROWS) return; // pixels outside the boundaries are ignored
if (color >> 24 == 0xff) // when full alpha, no need to do any RGB calculations
bitmapBuffer[y * COLS + x] = color;
else
bitmapBuffer[y * COLS + x] = addAlphaColor(x, y, color);
}
void setBackground(unsigned int color) {
for (int i = 0; i < COLS * ROWS; i++)
bitmapBuffer[i] = color;
}
void fillRectangle(char x1, char y1, char x2, char y2, unsigned int color) {
for (int x = x1; x <= x2; x++)
for (int y = y1; y <= y2; y++)
setPixel(x, y, color);
}
void drawLine(char x1, char y1, char x2, char y2, unsigned int color) {
if (x2 < x1) {
char temp = x1;
x1 = x2;
x2 = temp;
}
if (y2 < y1) {
char temp = y1;
y1 = y2;
y2 = temp;
}
float xPosInc = (x2 - x1 > y2 - y1) ? 1 : (float) (x2 - x1) / (float) (y2 - y1);
float yPosInc = (y2 - y1 > x2 - x1) ? 1 : (float) (y2 - y1) / (float) (x2 - x1);
float xpos = x1;
float ypos = y1;
for (int i = 0; i <= ((x2 - x1) > (y2 - y1) ? x2 - x1 : y2 - y1); i++) {
setPixel(xpos, ypos, color);
xpos += xPosInc;
ypos += yPosInc;
}
}
void drawRectangle(char x1, char y1, char x2, char y2, unsigned int color) {
drawLine(x1, y1, x2, y1, color); // top
drawLine(x1, y2, x2, y2, color); // bottom
drawLine(x1, y1, x1, y2, color); // left
drawLine(x2, y1, x2, y2, color); // right
}
// Not optimized but does the job
void drawCircle(char x, char y, char radius, unsigned int color) {
for (float angle = 0; angle < 3.142 * 2; angle += 0.1) {
setPixel(x + round(radius * cos(angle)), y + round(radius * sin(angle)), color);
}
}
int main() {
SYSTEMConfigPerformance(80000000L);
SYSTEMConfig(SYS_FREQ, SYS_CFG_WAIT_STATES | SYS_CFG_PCACHE);
mJTAGPortEnable(DEBUG_JTAGPORT_OFF);
PORTSetPinsDigitalOut(LEDPORT, LEDPIN);
OpenTimer1(T1_ON | T1_PS_1_256, 0xffffff);
unsigned char r[ROWS][COLS];
unsigned char i;
while (1) {
WriteTimer1(0);
setBackground(getARGB(0xff000002));
if (i++ % 2) {
char s1 = rand() % COLS;
char s2 = rand() % ROWS;
if (r[s1][s2] == 0)
r[s1][s2] = 1;
}
for (int y = 0; y < ROWS; y++)
for (int x = 0; x < COLS; x++) {
if (r[y][x] > 0) {
r[y][x]++;
if (r[y][x] < 128)
setPixel(x, y, getARGB(r[y][x], 0, 155, 0));
else
setPixel(x, y, getARGB(0xff - r[y][x], 0, 155, 0));
}
}
sendBitmapBuffer();
while (ReadTimer1() < 0x3ff) Nop();
}
return 0;
}
