Library for LPD8806 (and probably LPD8803/LPD8809) PWM LED driver chips, strips and pixels. Standard connected to 1st hardware SPI module. Data -> p5 and Clock -> p7 use a fixed sized buffer rather than malloc - if we use malloc rtos is unhappy...
Fork of LPD8806 by
LPD8806.cpp
- Committer:
- Jasper
- Date:
- 2014-05-30
- Revision:
- 2:5d654eba3240
- Parent:
- 1:6ebd3ac910b6
File content as of revision 2:5d654eba3240:
// Mbed library to control LPD8806-based RGB LED Strips // (c) 2011 Jelmer Tiete // This library is ported from the Arduino implementation of Adafruit Industries // found at: http://github.com/adafruit/LPD8806 // and their strips: http://www.adafruit.com/products/306 // Released under the MIT License: http://mbed.org/license/mit // // standard connected to 1st hardware SPI // LPD8806 <> MBED // DATA -> P5 // CLOCK -> p7 /*****************************************************************************/ #include "LPD8806.h" //Define SPI pins //Connected to first SPI module SPI spi(p5, p6, p7); // mosi, miso, sclk //SPI spi(p11, p12, p13); // mosi, miso, sclk LPD8806::LPD8806(uint16_t n) { // Allocate 3 bytes per pixel: // if (NULL != (pixels = (uint8_t *)malloc(numLEDs * 3))) { memset(pixels, 0x80, numLEDs * 3); // Init to RGB 'off' state numLEDs = n; // } } int LPD8806::pixels_ok(void) { if (pixels != NULL) return 1; else return 0; } void LPD8806::begin(void) { // Setup the spi for 8 bit data, low steady state clock, // first edge capture, with a 2MHz clock rate spi.format(8,0); spi.frequency(2000000); // Issue initial latch to 'wake up' strip (latch length varies w/numLEDs) writezeros(3 * ((numLEDs + 63) / 64)); } uint16_t LPD8806::numPixels(void) { return numLEDs; } void LPD8806::writezeros(uint16_t n) { while (n--) spi.write(0x00); } // This is how data is pushed to the strip. Unfortunately, the company // that makes the chip didnt release the protocol document or you need // to sign an NDA or something stupid like that, but we reverse engineered // this from a strip controller and it seems to work very nicely! void LPD8806::show(void) { uint16_t i, nl3 = numLEDs * 3; // 3 bytes per LED for (i=0; i<nl3; i++ ) { spi.write(pixels[i]); } // Write latch at end of data; latch length varies with number of LEDs writezeros(3 * ((numLEDs + 63) / 64)); // We need to have a delay here, a few ms seems to do the job // shorter may be OK as well - need to experiment :( wait_ms(3); } // Convert R,G,B to combined 32-bit color uint32_t LPD8806::Color(uint8_t r, uint8_t g, uint8_t b) { // Take the lowest 7 bits of each value and append them end to end // We have the top bit set high (its a 'parity-like' bit in the protocol // and must be set!) return 0x808080 | ((uint32_t)g << 16) | ((uint32_t)r << 8) | (uint32_t)b; } // store the rgb component in our array void LPD8806::setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b) { if (n >= numLEDs) return; // '>=' because arrays are 0-indexed pixels[(n * 3) ] = g | 0x80; pixels[(n * 3) +1 ] = r | 0x80; pixels[(n * 3) +2 ] = b | 0x80; } void LPD8806::setPixelColor(uint16_t n, uint32_t c) { if (n >= numLEDs) return; // '>=' because arrays are 0-indexed pixels[(n * 3) ] = ((c >> 16) & 0xff)| 0x80; pixels[(n * 3) + 1] = ((c >> 8) & 0xff)| 0x80; pixels[(n * 3) + 2] = ( c & 0xff)| 0x80; }