LEDsnake - LED screen snake as an example of 48x48 panelspac…

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Ryan Savitski / Mbed 2 deprecated 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[3PIXPERPANXPANS*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;//(iii)>>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 < 25633*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/(163) XPANS;
rsavitski	0:b38330b559d4	138
rsavitski	0:b38330b559d4	139	if (y%2 == 0)
rsavitski	0:b38330b559d4	140	{
rsavitski	0:b38330b559d4	141	t = (y%16)/20x20 + ((x%16)/80x10+(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)/20x20 + ((x%16)/80x10+(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[i2563*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	}

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Type:	Program
Mbed OS support:	Mbed 2 deprecated
Created:	22 Mar 2012
Imports:	6
Forks:	0
Commits:	1
Dependents:	0
Dependencies:	1
Followers:	1

ledScreen.h@0:b38330b559d4, 2012-03-22 (annotated)

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