Ryan Savitski
/
LEDsnake
LED screen snake as an example of 48x48 panelspace working.
ledScreen.h@0:b38330b559d4, 2012-03-22 (annotated)
- Committer:
- rsavitski
- Date:
- Thu Mar 22 13:20:53 2012 +0000
- Revision:
- 0:b38330b559d4
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
rsavitski | 0:b38330b559d4 | 1 | #include "mbed.h" |
rsavitski | 0:b38330b559d4 | 2 | |
rsavitski | 0:b38330b559d4 | 3 | /* |
rsavitski | 0:b38330b559d4 | 4 | collision detection |
rsavitski | 0:b38330b559d4 | 5 | dot |
rsavitski | 0:b38330b559d4 | 6 | scoring |
rsavitski | 0:b38330b559d4 | 7 | growth currently at tail? |
rsavitski | 0:b38330b559d4 | 8 | |
rsavitski | 0:b38330b559d4 | 9 | |
rsavitski | 0:b38330b559d4 | 10 | */ |
rsavitski | 0:b38330b559d4 | 11 | |
rsavitski | 0:b38330b559d4 | 12 | extern "C" void frameout(unsigned char dsVal[], unsigned char transformedSource[]); |
rsavitski | 0:b38330b559d4 | 13 | |
rsavitski | 0:b38330b559d4 | 14 | class ledScreen { |
rsavitski | 0:b38330b559d4 | 15 | public: |
rsavitski | 0:b38330b559d4 | 16 | ledScreen(); |
rsavitski | 0:b38330b559d4 | 17 | ~ledScreen() {} |
rsavitski | 0:b38330b559d4 | 18 | |
rsavitski | 0:b38330b559d4 | 19 | void transformFrame(unsigned char* imageSource); |
rsavitski | 0:b38330b559d4 | 20 | void outputFrame(); |
rsavitski | 0:b38330b559d4 | 21 | void start(); // start outputting frames on an interrupt |
rsavitski | 0:b38330b559d4 | 22 | |
rsavitski | 0:b38330b559d4 | 23 | private: |
rsavitski | 0:b38330b559d4 | 24 | |
rsavitski | 0:b38330b559d4 | 25 | int MAX_PULSE_WIDTH; // constant: max enable pulse duration |
rsavitski | 0:b38330b559d4 | 26 | int pulseLength; // length of current pulse (used in delta-sigma pwm) |
rsavitski | 0:b38330b559d4 | 27 | int OP_TIME; |
rsavitski | 0:b38330b559d4 | 28 | |
rsavitski | 0:b38330b559d4 | 29 | static const int XPANS = 3; // number of panels horizontally |
rsavitski | 0:b38330b559d4 | 30 | static const int YUNITS = 1; |
rsavitski | 0:b38330b559d4 | 31 | static const int YPANS = 3; // 3* YUNITS |
rsavitski | 0:b38330b559d4 | 32 | static const int PIXPERPAN = 256; |
rsavitski | 0:b38330b559d4 | 33 | |
rsavitski | 0:b38330b559d4 | 34 | int running; |
rsavitski | 0:b38330b559d4 | 35 | int subFrameCtr; |
rsavitski | 0:b38330b559d4 | 36 | |
rsavitski | 0:b38330b559d4 | 37 | Timeout nextFrameTimer; // timeout routine |
rsavitski | 0:b38330b559d4 | 38 | |
rsavitski | 0:b38330b559d4 | 39 | // Buffers to hold the RGB data after rearranging to match the LED shifting pattern |
rsavitski | 0:b38330b559d4 | 40 | unsigned char transformedSource[3*PIXPERPAN*XPANS*YPANS]; |
rsavitski | 0:b38330b559d4 | 41 | |
rsavitski | 0:b38330b559d4 | 42 | // Error values for all 256 brightness levels |
rsavitski | 0:b38330b559d4 | 43 | unsigned int dsErr[256]; |
rsavitski | 0:b38330b559d4 | 44 | unsigned int ssdsErr[256]; |
rsavitski | 0:b38330b559d4 | 45 | |
rsavitski | 0:b38330b559d4 | 46 | // On/off state per sub-frame for all 256 brightness levels |
rsavitski | 0:b38330b559d4 | 47 | unsigned char dsVal[256]; |
rsavitski | 0:b38330b559d4 | 48 | |
rsavitski | 0:b38330b559d4 | 49 | // Precomputed gamma for all 256 brightness levels |
rsavitski | 0:b38330b559d4 | 50 | unsigned short gamma[256]; |
rsavitski | 0:b38330b559d4 | 51 | |
rsavitski | 0:b38330b559d4 | 52 | |
rsavitski | 0:b38330b559d4 | 53 | DigitalOut flatch; // data latch (for all connected panels in parallel) |
rsavitski | 0:b38330b559d4 | 54 | DigitalOut MA0; // module address 0 |
rsavitski | 0:b38330b559d4 | 55 | DigitalOut MA1; |
rsavitski | 0:b38330b559d4 | 56 | DigitalOut NREN; // active low enable for red channel (low -> LED on). Note: need to have enable high when latching data |
rsavitski | 0:b38330b559d4 | 57 | DigitalOut Rdat0; // red data |
rsavitski | 0:b38330b559d4 | 58 | DigitalOut Gdat0; // green data |
rsavitski | 0:b38330b559d4 | 59 | DigitalOut Bdat0; // blue data |
rsavitski | 0:b38330b559d4 | 60 | DigitalOut Rdat1; // red data |
rsavitski | 0:b38330b559d4 | 61 | DigitalOut Gdat1; // green data |
rsavitski | 0:b38330b559d4 | 62 | DigitalOut Bdat1; // blue data |
rsavitski | 0:b38330b559d4 | 63 | DigitalOut Rdat2; // red data |
rsavitski | 0:b38330b559d4 | 64 | DigitalOut Gdat2; // green data |
rsavitski | 0:b38330b559d4 | 65 | DigitalOut Bdat2; // blue data |
rsavitski | 0:b38330b559d4 | 66 | DigitalOut sclk; // clock |
rsavitski | 0:b38330b559d4 | 67 | |
rsavitski | 0:b38330b559d4 | 68 | DigitalOut debug; |
rsavitski | 0:b38330b559d4 | 69 | |
rsavitski | 0:b38330b559d4 | 70 | }; |
rsavitski | 0:b38330b559d4 | 71 | |
rsavitski | 0:b38330b559d4 | 72 | ledScreen::ledScreen() : |
rsavitski | 0:b38330b559d4 | 73 | flatch(p10), // data latch (for all connected panels in parallel) |
rsavitski | 0:b38330b559d4 | 74 | MA0(p23), // module address 0 |
rsavitski | 0:b38330b559d4 | 75 | MA1(p24), |
rsavitski | 0:b38330b559d4 | 76 | NREN(p9), // active low enable for red channel (low -> LED on). Note: need to have enable high when latching data |
rsavitski | 0:b38330b559d4 | 77 | Rdat0(p15), // red data |
rsavitski | 0:b38330b559d4 | 78 | Gdat0(p16), // green data |
rsavitski | 0:b38330b559d4 | 79 | Bdat0(p17), // blue data |
rsavitski | 0:b38330b559d4 | 80 | Rdat1(p7), // red data |
rsavitski | 0:b38330b559d4 | 81 | Gdat1(p6), // green data |
rsavitski | 0:b38330b559d4 | 82 | Bdat1(p5), // blue data |
rsavitski | 0:b38330b559d4 | 83 | Rdat2(p13), // red data |
rsavitski | 0:b38330b559d4 | 84 | Gdat2(p12), // green data |
rsavitski | 0:b38330b559d4 | 85 | Bdat2(p11), // blue data |
rsavitski | 0:b38330b559d4 | 86 | sclk(p14), |
rsavitski | 0:b38330b559d4 | 87 | debug(p27) { // clock |
rsavitski | 0:b38330b559d4 | 88 | |
rsavitski | 0:b38330b559d4 | 89 | // precompute gamma for every possible RGB intensity value (0-255). |
rsavitski | 0:b38330b559d4 | 90 | // Gamma correction with gamma = 3, downshifting by 8 to bring the range of values back to 0-65535 |
rsavitski | 0:b38330b559d4 | 91 | for (int i=0; i<256; i++) { |
rsavitski | 0:b38330b559d4 | 92 | gamma[i] = pow(i, 2.2) * 0.33;//(i*i*i)>>8; |
rsavitski | 0:b38330b559d4 | 93 | } |
rsavitski | 0:b38330b559d4 | 94 | |
rsavitski | 0:b38330b559d4 | 95 | // initialising lines |
rsavitski | 0:b38330b559d4 | 96 | flatch = 1; |
rsavitski | 0:b38330b559d4 | 97 | NREN = 1; |
rsavitski | 0:b38330b559d4 | 98 | sclk = 1; |
rsavitski | 0:b38330b559d4 | 99 | |
rsavitski | 0:b38330b559d4 | 100 | // initialising values |
rsavitski | 0:b38330b559d4 | 101 | MAX_PULSE_WIDTH = 512; //must currently be a power of 2, and when changing this, you must change the ssdsErr crossover masking |
rsavitski | 0:b38330b559d4 | 102 | pulseLength = MAX_PULSE_WIDTH; |
rsavitski | 0:b38330b559d4 | 103 | OP_TIME = 510; //Determined by scoping. Change this every time you change num screens |
rsavitski | 0:b38330b559d4 | 104 | //NUM_PANELS = 3 |
rsavitski | 0:b38330b559d4 | 105 | |
rsavitski | 0:b38330b559d4 | 106 | running=0; |
rsavitski | 0:b38330b559d4 | 107 | subFrameCtr=0; |
rsavitski | 0:b38330b559d4 | 108 | |
rsavitski | 0:b38330b559d4 | 109 | // initialising errors for delta-sigma |
rsavitski | 0:b38330b559d4 | 110 | for (int j=0; j<256; j++) { |
rsavitski | 0:b38330b559d4 | 111 | dsErr[j] = 0; |
rsavitski | 0:b38330b559d4 | 112 | ssdsErr[j] = 0; |
rsavitski | 0:b38330b559d4 | 113 | } |
rsavitski | 0:b38330b559d4 | 114 | |
rsavitski | 0:b38330b559d4 | 115 | } |
rsavitski | 0:b38330b559d4 | 116 | |
rsavitski | 0:b38330b559d4 | 117 | void ledScreen::start() { |
rsavitski | 0:b38330b559d4 | 118 | outputFrame(); |
rsavitski | 0:b38330b559d4 | 119 | } |
rsavitski | 0:b38330b559d4 | 120 | |
rsavitski | 0:b38330b559d4 | 121 | |
rsavitski | 0:b38330b559d4 | 122 | |
rsavitski | 0:b38330b559d4 | 123 | void ledScreen::transformFrame(unsigned char* imageSource) |
rsavitski | 0:b38330b559d4 | 124 | { |
rsavitski | 0:b38330b559d4 | 125 | int i=0; |
rsavitski | 0:b38330b559d4 | 126 | int panseqnum=0, t=0, out=0, x=0, y=0; |
rsavitski | 0:b38330b559d4 | 127 | |
rsavitski | 0:b38330b559d4 | 128 | for (int q=0; q < 256*3*3*3; q+=3) |
rsavitski | 0:b38330b559d4 | 129 | { |
rsavitski | 0:b38330b559d4 | 130 | i = q/3; |
rsavitski | 0:b38330b559d4 | 131 | |
rsavitski | 0:b38330b559d4 | 132 | x = i % (16*XPANS); |
rsavitski | 0:b38330b559d4 | 133 | y = i / (16*XPANS); |
rsavitski | 0:b38330b559d4 | 134 | |
rsavitski | 0:b38330b559d4 | 135 | |
rsavitski | 0:b38330b559d4 | 136 | int MA = (y/16) % 3; |
rsavitski | 0:b38330b559d4 | 137 | panseqnum = x/16 + y/(16*3) * XPANS; |
rsavitski | 0:b38330b559d4 | 138 | |
rsavitski | 0:b38330b559d4 | 139 | if (y%2 == 0) |
rsavitski | 0:b38330b559d4 | 140 | { |
rsavitski | 0:b38330b559d4 | 141 | t = (y%16)/2*0x20 + ((x%16)/8*0x10+(7-(x%16)%8)); |
rsavitski | 0:b38330b559d4 | 142 | } |
rsavitski | 0:b38330b559d4 | 143 | else |
rsavitski | 0:b38330b559d4 | 144 | { |
rsavitski | 0:b38330b559d4 | 145 | t = 8 + (y%16)/2*0x20 + ((x%16)/8*0x10+(x%16)%8); |
rsavitski | 0:b38330b559d4 | 146 | } |
rsavitski | 0:b38330b559d4 | 147 | |
rsavitski | 0:b38330b559d4 | 148 | out = 3*(MA * YUNITS * XPANS * 256 + t * XPANS * YUNITS + panseqnum); |
rsavitski | 0:b38330b559d4 | 149 | |
rsavitski | 0:b38330b559d4 | 150 | transformedSource[out] = imageSource[q]; |
rsavitski | 0:b38330b559d4 | 151 | transformedSource[out+1] = imageSource[q+1]; |
rsavitski | 0:b38330b559d4 | 152 | transformedSource[out+2] = imageSource[q+2]; |
rsavitski | 0:b38330b559d4 | 153 | } |
rsavitski | 0:b38330b559d4 | 154 | |
rsavitski | 0:b38330b559d4 | 155 | } |
rsavitski | 0:b38330b559d4 | 156 | |
rsavitski | 0:b38330b559d4 | 157 | // Output one frame and call itself after a period of time if running is set to true |
rsavitski | 0:b38330b559d4 | 158 | void ledScreen::outputFrame() { |
rsavitski | 0:b38330b559d4 | 159 | |
rsavitski | 0:b38330b559d4 | 160 | debug = 1; |
rsavitski | 0:b38330b559d4 | 161 | |
rsavitski | 0:b38330b559d4 | 162 | NREN = 0; // turn off |
rsavitski | 0:b38330b559d4 | 163 | |
rsavitski | 0:b38330b559d4 | 164 | if (subFrameCtr<=0) subFrameCtr=36; |
rsavitski | 0:b38330b559d4 | 165 | subFrameCtr--; |
rsavitski | 0:b38330b559d4 | 166 | |
rsavitski | 0:b38330b559d4 | 167 | if (subFrameCtr == 0) { // Every cycle of delta sigma we take a snapshot of the error that needs to be corrected by the short pulses. |
rsavitski | 0:b38330b559d4 | 168 | for (int i = 0; i < 256; i++) { // This is required to eliminate visible flicker due to beat frequencies otherwise created. |
rsavitski | 0:b38330b559d4 | 169 | dsErr[i] += ssdsErr[i] & 0xFE000000; |
rsavitski | 0:b38330b559d4 | 170 | ssdsErr[i] %= 0x10000; |
rsavitski | 0:b38330b559d4 | 171 | ssdsErr[i] += dsErr[i] % (512 * 0x10000); |
rsavitski | 0:b38330b559d4 | 172 | dsErr[i] &= 0xFE000000; |
rsavitski | 0:b38330b559d4 | 173 | } |
rsavitski | 0:b38330b559d4 | 174 | |
rsavitski | 0:b38330b559d4 | 175 | // Doing delta sigma for the snapshot |
rsavitski | 0:b38330b559d4 | 176 | for (int i = 0; i <= 9; i++) { |
rsavitski | 0:b38330b559d4 | 177 | int lpl = 1<<i; |
rsavitski | 0:b38330b559d4 | 178 | |
rsavitski | 0:b38330b559d4 | 179 | if (ssdsErr[i]/0x10000 & lpl) |
rsavitski | 0:b38330b559d4 | 180 | ssdsErr[i]-=(0x10000-gamma[i])*lpl; |
rsavitski | 0:b38330b559d4 | 181 | else |
rsavitski | 0:b38330b559d4 | 182 | ssdsErr[i]+=gamma[i]*lpl; |
rsavitski | 0:b38330b559d4 | 183 | } |
rsavitski | 0:b38330b559d4 | 184 | |
rsavitski | 0:b38330b559d4 | 185 | } |
rsavitski | 0:b38330b559d4 | 186 | |
rsavitski | 0:b38330b559d4 | 187 | // produce pulse lengths of 1, 2, 4, ... 256, spread throughout all subframes (only one in four are not MAX_PULSE_WIDTH long) |
rsavitski | 0:b38330b559d4 | 188 | pulseLength = ((subFrameCtr%4)?MAX_PULSE_WIDTH:(1<<(subFrameCtr>>2))); |
rsavitski | 0:b38330b559d4 | 189 | |
rsavitski | 0:b38330b559d4 | 190 | for (int i = 0; i < 256; i++) { |
rsavitski | 0:b38330b559d4 | 191 | if (pulseLength == MAX_PULSE_WIDTH) { |
rsavitski | 0:b38330b559d4 | 192 | // Delta-Sigma modulation with variable pulse length weighting |
rsavitski | 0:b38330b559d4 | 193 | // Based on energy dimensions (time * amplitude) |
rsavitski | 0:b38330b559d4 | 194 | if (dsErr[i] > (0x10000-gamma[i])*pulseLength) { |
rsavitski | 0:b38330b559d4 | 195 | dsVal[i] = 0;//-1; Invert as we are using inverting buffers |
rsavitski | 0:b38330b559d4 | 196 | dsErr[i]-=(0x10000-gamma[i])*pulseLength; |
rsavitski | 0:b38330b559d4 | 197 | } else { |
rsavitski | 0:b38330b559d4 | 198 | dsVal[i] = (unsigned char)-1; |
rsavitski | 0:b38330b559d4 | 199 | dsErr[i]+=gamma[i]*pulseLength; |
rsavitski | 0:b38330b559d4 | 200 | } |
rsavitski | 0:b38330b559d4 | 201 | } else { // if short pulse |
rsavitski | 0:b38330b559d4 | 202 | if (ssdsErr[i]/0x10000 & pulseLength) { |
rsavitski | 0:b38330b559d4 | 203 | //Doing proper least significant delta sigma live still causes flicker (but only for dim pixels) |
rsavitski | 0:b38330b559d4 | 204 | //ssdsErr[i]-=(0x10000-gamma[i])*pulseLength; |
rsavitski | 0:b38330b559d4 | 205 | dsVal[i] = 0; |
rsavitski | 0:b38330b559d4 | 206 | } else { |
rsavitski | 0:b38330b559d4 | 207 | dsVal[i] = (unsigned char)-1; |
rsavitski | 0:b38330b559d4 | 208 | } |
rsavitski | 0:b38330b559d4 | 209 | |
rsavitski | 0:b38330b559d4 | 210 | } |
rsavitski | 0:b38330b559d4 | 211 | } |
rsavitski | 0:b38330b559d4 | 212 | |
rsavitski | 0:b38330b559d4 | 213 | // output data |
rsavitski | 0:b38330b559d4 | 214 | for (int i = 0; i < 3; i++) { |
rsavitski | 0:b38330b559d4 | 215 | MA0 = !(i&1); |
rsavitski | 0:b38330b559d4 | 216 | MA1 = !(i&2); |
rsavitski | 0:b38330b559d4 | 217 | |
rsavitski | 0:b38330b559d4 | 218 | frameout(dsVal, &transformedSource[i*256*3*3]); |
rsavitski | 0:b38330b559d4 | 219 | } |
rsavitski | 0:b38330b559d4 | 220 | |
rsavitski | 0:b38330b559d4 | 221 | NREN = 0; // need to have enables high before every latch, (in case we are on a long pulse) |
rsavitski | 0:b38330b559d4 | 222 | flatch = 0; // latching all data to LEDs |
rsavitski | 0:b38330b559d4 | 223 | flatch = 1; |
rsavitski | 0:b38330b559d4 | 224 | NREN = 1; // turn on LEDs |
rsavitski | 0:b38330b559d4 | 225 | |
rsavitski | 0:b38330b559d4 | 226 | if (pulseLength < 4) { // short pulses done through wait |
rsavitski | 0:b38330b559d4 | 227 | wait_us(pulseLength); |
rsavitski | 0:b38330b559d4 | 228 | NREN = 0; //Turn off LEDs |
rsavitski | 0:b38330b559d4 | 229 | outputFrame(); //this will recurse only once due to the distrubution of pulses. pulseLength of the next instance will be attached. |
rsavitski | 0:b38330b559d4 | 230 | } |
rsavitski | 0:b38330b559d4 | 231 | else |
rsavitski | 0:b38330b559d4 | 232 | { |
rsavitski | 0:b38330b559d4 | 233 | // long waits done through attaching an interrupt that will turn off the LEDs at the start of next function call. |
rsavitski | 0:b38330b559d4 | 234 | // Meanwhile, the main code can run between the interrupts. |
rsavitski | 0:b38330b559d4 | 235 | nextFrameTimer.attach_us(this, &ledScreen::outputFrame, pulseLength); |
rsavitski | 0:b38330b559d4 | 236 | debug = 0; |
rsavitski | 0:b38330b559d4 | 237 | } |
rsavitski | 0:b38330b559d4 | 238 | } |