Revision 0:8b26631e8c70, committed 2012-03-06

Comitter:

rsavitski

Date:

Tue Mar 06 19:58:34 2012 +0000

Commit message:

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/frameout.s	Tue Mar 06 19:58:34 2012 +0000
@@ -0,0 +1,146 @@
+    AREA framefunc, CODE, READONLY
+; Export my_asm function location so that C compiler can find it and link
+    EXPORT frameout
+frameout
+
+; r0 - dsVal array base address
+; r1 - data array base address
+; r2 - base address for port 0
+; r3 - loop counter
+; r4 - sclk bitmask
+; r5 - RGB channels bitmask
+; r6 - data reg 1
+; r7 - data reg 2
+; r8 - temporary value holding intensity info (used as an offset into dsVal array)
+
+
+; Save state
+    PUSH {R4, R5, R6, R7, R8}
+
+; Load GPIO Port 0 base address in register R6 
+    LDR     R2, =0x2009C000 ; GPIO port 0 base address
+    
+; R3 - loop counter
+    MOV     R3, #256
+    
+; sclk mask
+    MOV     R4, #0x00010000 ; sclk bitmask
+    
+LOOP
+    
+;NOTE clocking swapped due to inverter used for logic levels
+    
+    MOV     R5, #0x03800000 ; bitmask for RGB bits
+    STR     R4, [R2, #0x1C] ; cleark clk to clock in data (negative edge)
+
+    
+    STR     R5, [R2, #0x1C] ; clear RGB via FIOCLEAR
+    
+    ; R channel
+    LDRB     R8, [R1], #1 ; read data word (0-255 intensity) and post-increment array pointer to point to next word in data
+    LDRB     R6, [R0, R8] ; loading on/off state from dsVal, pointed to by offset equal to intensity of data
+        
+  
+    ; G channel  
+    LDRB     R8, [R1], #1 ; read data word (0-255 intensity) into R8 and post-increment to point to next word in data
+    LDRB     R7, [R0, R8] ; loading on/off state from dsVal, pointed to by offset equal to intensity of data
+    
+    AND     R7, R7, #0x2 ; pick blue channel bit
+    
+    ORR     R6, R7, R6, lsr #7 ; store RG bits in R6 with clever stuff in R chan
+    
+    ; B channel
+    LDRB     R8, [R1], #1 ; read data word (0-255 intensity) into R8 and post-increment to point to next word in data
+    LDRB     R7, [R0, R8] ; loading on/off state from dsVal, pointed to by offset equal to intensity of data    
+    
+    AND     R7, R7, #0x4 ; pick green channel bit
+    
+    ; writing to output
+    ORR     R6, R6, R7 ; RGB bits in R6
+    
+    MOV     R6, R6, lsl #23 
+
+    STR     R6, [R2,#0x18] ; FIOSET on/off for LED
+    
+    ;SUB     R1, R1, #3
+    
+    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+    
+    
+    MOV     R5, #0x00000380 ; bitmask for RGB bits
+    
+    STR     R5, [R2, #0x1C] ; clear RGB via FIOCLEAR
+    
+    ; R channel
+    LDRB     R8, [R1], #1 ; read data word (0-255 intensity) and post-increment array pointer to point to next word in data
+    LDRB     R6, [R0, R8] ; loading on/off state from dsVal, pointed to by offset equal to intensity of data
+        
+  
+    ; G channel  
+    LDRB     R8, [R1], #1 ; read data word (0-255 intensity) into R8 and post-increment to point to next word in data
+    LDRB     R7, [R0, R8] ; loading on/off state from dsVal, pointed to by offset equal to intensity of data
+    
+    AND     R7, R7, #0x2 ; pick blue channel bit
+    
+    ORR     R6, R7, R6, lsr #7 ; store RG bits in R6 with clever stuff in R chan
+    
+    ; B channel
+    LDRB     R8, [R1], #1 ; read data word (0-255 intensity) into R8 and post-increment to point to next word in data
+    LDRB     R7, [R0, R8] ; loading on/off state from dsVal, pointed to by offset equal to intensity of data    
+    
+    AND     R7, R7, #0x4 ; pick green channel bit
+    
+    ; writing to output
+    ORR     R6, R6, R7 ; RGB bits in R6
+    
+    MOV     R6, R6, lsl #7 
+
+    STR     R6, [R2,#0x18] ; FIOSET on/off for LED
+    
+    ;SUB     R1, R1, #3
+    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+    
+        
+    MOV     R5, #0x00068000 ; bitmask for RGB bits
+    
+    STR     R5, [R2, #0x1C] ; clear RGB via FIOCLEAR
+    
+    ; R channel
+    LDRB     R8, [R1], #1 ; read data word (0-255 intensity) and post-increment array pointer to point to next word in data
+    LDRB     R6, [R0, R8] ; loading on/off state from dsVal, pointed to by offset equal to intensity of data
+        
+  
+    ; G channel  
+    LDRB     R8, [R1], #1 ; read data word (0-255 intensity) into R8 and post-increment to point to next word in data
+    LDRB     R7, [R0, R8] ; loading on/off state from dsVal, pointed to by offset equal to intensity of data
+    
+    AND     R7, R7, #0x4 ; pick blue channel bit
+    
+    ORR     R6, R7, R6, lsr #7 ; store RG bits in R6 with clever stuff in R chan
+    
+    ; B channel
+    LDRB     R8, [R1], #1 ; read data word (0-255 intensity) into R8 and post-increment to point to next word in data
+    LDRB     R7, [R0, R8] ; loading on/off state from dsVal, pointed to by offset equal to intensity of data    
+    
+    AND     R7, R7, #0x8 ; pick green channel bit
+    
+    ; writing to output
+    ORR     R6, R6, R7 ; RGB bits in R6
+    
+    MOV     R6, R6, lsl #15 
+
+    STR     R6, [R2,#0x18] ; FIOSET on/off for LED
+    
+    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+    
+    SUBS    R3, R3, #0x1 ; decrement loop counter
+
+    STR     R4, [R2, #0x18] ; setting clock high
+    
+    
+    BNE     LOOP
+    
+    POP {R4, R5, R6, R7, R8}
+
+    BX      LR
+    END

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ledScreen.h	Tue Mar 06 19:58:34 2012 +0000
@@ -0,0 +1,238 @@
+#include "mbed.h"
+
+/*
+    TODO: wasrunning - works as intended?
+    TODO: OPTIME - tweak value
+
+*/
+
+extern "C" void frameout(unsigned char dsVal[], unsigned char transformedSource[]);
+
+class ledScreen {
+public:
+    ledScreen();
+    ~ledScreen() {}
+
+    void transformFrame(unsigned char* imageSource);
+    void outputFrame();
+    void start();   // start outputting frames on an interrupt
+
+private:
+
+    int MAX_PULSE_WIDTH; // constant: max enable pulse duration
+    int pulseLength; // length of current pulse (used in delta-sigma pwm)
+    int OP_TIME;
+
+    static const int XPANS = 3; // number of panels horizontally
+    static const int YUNITS = 1;
+    static const int YPANS = 3; // 3* YUNITS
+    static const int PIXPERPAN = 256;
+
+    int running;
+    int subFrameCtr;
+
+    Timeout nextFrameTimer; // timeout routine
+
+    // Buffers to hold the RGB data after rearranging to match the LED shifting pattern
+    unsigned char transformedSource[3*PIXPERPAN*XPANS*YPANS];
+
+    // Error values for all 256 brightness levels
+    unsigned int dsErr[256];
+    unsigned int ssdsErr[256];
+
+    // On/off state per sub-frame for all 256 brightness levels
+    unsigned char dsVal[256];
+
+    // Precomputed gamma for all 256 brightness levels
+    unsigned short gamma[256];
+
+
+    DigitalOut flatch; // data latch (for all connected panels in parallel)
+    DigitalOut MA0; // module address 0
+    DigitalOut MA1;
+    DigitalOut NREN; // active low enable for red channel (low -> LED on). Note: need to have enable high when latching data
+    DigitalOut Rdat0; // red data
+    DigitalOut Gdat0; // green data
+    DigitalOut Bdat0; // blue data
+    DigitalOut Rdat1; // red data
+    DigitalOut Gdat1; // green data
+    DigitalOut Bdat1; // blue data
+    DigitalOut Rdat2; // red data
+    DigitalOut Gdat2; // green data
+    DigitalOut Bdat2; // blue data
+    DigitalOut sclk; // clock
+    
+    DigitalOut debug;
+
+};
+
+ledScreen::ledScreen() :
+        flatch(p10), // data latch (for all connected panels in parallel)
+        MA0(p18), // module address 0
+        MA1(p19),
+        NREN(p9), // active low enable for red channel (low -> LED on). Note: need to have enable high when latching data
+        Rdat0(p15), // red data
+        Gdat0(p16), // green data
+        Bdat0(p17), // blue data
+        Rdat1(p7), // red data
+        Gdat1(p6), // green data
+        Bdat1(p5), // blue data
+        Rdat2(p13), // red data
+        Gdat2(p12), // green data
+        Bdat2(p11), // blue data
+        sclk(p14),
+        debug(p27) { // clock
+
+    // precompute gamma for every possible RGB intensity value (0-255).
+    // Gamma correction with gamma = 3, downshifting by 8 to bring the range of values back to 0-65535
+    for (int i=0; i<256; i++) {
+        gamma[i] = pow(i, 2.2) * 0.33;//(i*i*i)>>8;
+    }
+
+    // initialising lines
+    flatch = 1;
+    NREN = 1;
+    sclk = 1;
+
+    // initialising values
+    MAX_PULSE_WIDTH = 512; //must currently be a power of 2, and when changing this, you must change the ssdsErr crossover masking
+    pulseLength = MAX_PULSE_WIDTH;
+    OP_TIME = 510; //Determined by scoping. Change this every time you change num screens
+    //NUM_PANELS = 3
+
+    running=0;
+    subFrameCtr=0;
+
+    // initialising errors for delta-sigma
+    for (int j=0; j<256; j++) {
+        dsErr[j] = 0;
+        ssdsErr[j] = 0;
+    }
+
+}
+
+void ledScreen::start() {
+    running=1;
+    outputFrame();
+}
+
+
+
+void ledScreen::transformFrame(unsigned char* imageSource)
+{
+    int i=0;
+    int panseqnum=0, t=0, out=0, x=0, y=0, MA=0;
+
+    for (int q=0; q < 256*3*3*3; q+=3)
+    {
+        i = q/3;
+        
+        x = i % (16*XPANS);
+        y = i / (16*XPANS);
+        
+        
+        int MA = (y/16) % 3;
+        panseqnum = x/16 + y/(16*3) * XPANS;
+       
+        if (y%2 == 0)
+        {
+                t = (y%16)/2*0x20 + ((x%16)/8*0x10+(7-(x%16)%8));
+        }
+        else
+        {
+                t = 8 + (y%16)/2*0x20 + ((x%16)/8*0x10+(x%16)%8);
+        }
+       
+        out = 3*(MA * YUNITS * XPANS * 256 + t * XPANS * YUNITS + panseqnum);
+        
+        transformedSource[out] = imageSource[q];
+        transformedSource[out+1] = imageSource[q+1];
+        transformedSource[out+2] = imageSource[q+2];
+    }
+
+}
+
+// Output one frame and call itself after a period of time if running is set to true
+void ledScreen::outputFrame() {
+
+    debug = 1;
+
+    if (pulseLength != MAX_PULSE_WIDTH)
+        NREN = 0; // turn off
+
+    if (subFrameCtr<=0) subFrameCtr=36;
+    subFrameCtr--;
+
+    if (subFrameCtr == 0) {                  // Every cycle of delta sigma we take a snapshot of the error that needs to be corrected by the short pulses.
+        for (int i = 0; i < 256; i++) {      // This is required to eliminate visible flicker due to beat frequencies otherwise created.
+            dsErr[i] += ssdsErr[i] & 0xFE000000;
+            ssdsErr[i] %= 0x10000;
+            ssdsErr[i] += dsErr[i] % (512 * 0x10000);
+            dsErr[i] &= 0xFE000000;
+        }
+
+        // Doing delta sigma for the snapshot
+        for (int i = 0; i <= 9; i++) {
+            int lpl = 1<<i;
+
+            if (ssdsErr[i]/0x10000 & lpl)
+                ssdsErr[i]-=(0x10000-gamma[i])*lpl;
+            else
+                ssdsErr[i]+=gamma[i]*lpl;
+        }
+
+    }
+
+    // produce pulse lengths of 1, 2, 4, ... 256, spread throughout all subframes (only one in four are not MAX_PULSE_WIDTH long)
+    pulseLength = ((subFrameCtr%4)?MAX_PULSE_WIDTH:(1<<(subFrameCtr>>2)));
+
+    for (int i = 0; i < 256; i++) {
+        if (pulseLength == MAX_PULSE_WIDTH) {
+            // Delta-Sigma modulation with variable pulse length weighting
+            // Based on energy dimensions (time * amplitude)
+            if (dsErr[i] > (0x10000-gamma[i])*pulseLength) {
+                dsVal[i] = 0;//-1; Invert as we are using inverting buffers
+                dsErr[i]-=(0x10000-gamma[i])*pulseLength;
+            } else {
+                dsVal[i] = (unsigned char)-1;
+                dsErr[i]+=gamma[i]*pulseLength;
+            }
+        } else { // if short pulse
+            if (ssdsErr[i]/0x10000 & pulseLength) {
+                //Doing proper least significant delta sigma live still causes flicker (but only for dim pixels)
+                //ssdsErr[i]-=(0x10000-gamma[i])*pulseLength;
+                dsVal[i] = 0;
+            } else {
+                dsVal[i] = (unsigned char)-1;
+            }
+
+        }
+    }
+
+    // output data
+    for (int i = 0; i < 3; i++) { //FIX
+        MA0 = !(i&1);
+        MA1 = !(i&2);
+
+        frameout(dsVal, &transformedSource[i*256*3*3]);
+    }
+
+    NREN = 0; // need to have enables high before every latch, (in case we are on a long pulse)
+    flatch = 0; // latching all data to LEDs
+    flatch = 1;
+    NREN = 1; // turn on LEDs
+
+    if (pulseLength < 4) { // short pulses done through wait
+        wait_us(pulseLength);
+        NREN = 0; //Turn off LEDs
+
+        bool wasrunning = running;
+        running = false;
+        outputFrame(); //this will recurse only once due to the distrubution of pulses. pulseLength of the next instance will be attached.
+        running = wasrunning;
+    }
+    // long waits done through attaching an interrupt that will turn off the LEDs at the start of next function call.
+    // Meanwhile, the main code can run between the interrupts.
+    if (running) nextFrameTimer.attach_us(this, &ledScreen::outputFrame, (pulseLength == MAX_PULSE_WIDTH) ? pulseLength - OP_TIME : pulseLength);
+    debug = 0;
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Mar 06 19:58:34 2012 +0000
@@ -0,0 +1,121 @@
+#include "mbed.h"
+#include "ledScreen.h"
+
+// screen instance
+ledScreen screen;
+
+// sin lookup table and related functions
+unsigned char sinlut[256];
+
+void initSinLut() {
+    for (int i=0; i<256; i++)
+        sinlut[i] = cos((float)i / 256.0 * (3.14159265 * 2))*127 + 128;
+}
+
+inline unsigned char lut_sin(int x) {
+
+    return (x>0)?sinlut[x%256]:sinlut[(-x)%256];
+}
+
+
+// Example frame makes:
+
+
+//rainbow
+void makeFrame1(unsigned char* data) {
+
+    static int time=0;
+    time++;
+    
+    // override data with a intensity gradient test pattern
+    for (int x=0; x<3*16; x++) {
+        for (int y=0; y<48; y++) {
+
+            int i = (x + y*(16*3)) * 3;  // figure out the memory location
+
+            data[i] = lut_sin((x+y)*255/48+(time/2)%256); //(sin((float)(x+time)/15.0)+1.0)*128 ;   // red
+            data[i+1] = lut_sin(((x+y)*255/48+(time/2)+ 85)%256); //(sin((float)(x+time)/15.0)+1.0)*128 ;   // red
+            data[i+2] = lut_sin(((x+y)*255/48+(time/2)+170)%256); //(sin((float)(x+time)/15.0)+1.0)*128 ;   // red
+        }
+    }
+
+}
+
+//cool lines
+void makeFrame2(unsigned char* data) {
+
+    static int time=0;
+    time++;
+    
+    // override data with a intensity gradient test pattern
+    for (int x=0; x<3*16; x++) {
+        for (int y=0; y<16; y++) {
+
+            int i = (x + y*(16*3)) * 3;  // figure out the memory location
+
+            data[i] = lut_sin(x*255/48+(time)%256 + y*16); //(sin((float)(x+time)/15.0)+1.0)*128 ;   // red
+            data[i+1] = lut_sin(x*255/48+(time)%256 + y*16 + 85); //(sin((float)(x+time)/15.0)+1.0)*128 ;   // red
+            data[i+2] = lut_sin(x*255/48+(time)%256 + y*16 + 170); //(sin((float)(x+time)/15.0)+1.0)*128 ;   // red
+        }
+    }
+
+}
+
+// static gradients
+void makeFrame3(unsigned char* data) {
+
+    static int time=0;
+    time++;
+
+    // override data with a intensity gradient test pattern
+    for (int x=0; x<3*16; x++) {
+        for (int y=0; y<16; y++) {
+
+            int i = (x + y*(16*3)) * 3;  // figure out the memory location
+
+            data[i] = x*256/48; //(sin((float)(x+time)/15.0)+1.0)*128 ;   // red
+            data[i+1] = 0;  // green
+            data[i+2] = y*256/16; //(i/3)%256 ; // blue
+        }
+    }
+
+}
+
+
+void makeFrame33(unsigned char* data) {
+
+    static int time=0;
+    time++;
+
+    for (int x=0; x<3*16; x++) {
+        for (int y=0; y<48; y++) {
+
+            int i = (x + y*(16*3)) * 3;  // figure out the memory location
+
+            data[i] = x*256/48; //(sin((float)(x+time)/15.0)+1.0)*128 ;   // red
+            data[i+1] = 0;  // green
+            data[i+2] = y*256/48; //(i/3)%256 ; // blue
+        }
+    }
+}
+ 
+int main()
+{
+
+    // framebuffer on client side
+    unsigned char imageSource[256*3*3*3] = { 0 };
+    
+    // prepare sin lookup table (optional)
+    initSinLut(); 
+
+    // start the screen output, which will keep outputting the frames that are in its internal buffer (updated via .transformFrame)
+    screen.start();
+
+    while (1) {
+        
+        makeFrame1(imageSource);  // prepare framebuffer with current frame
+        screen.transformFrame(imageSource); // write framebuffer to output framebuffer
+        wait_ms(0.5); // slow down the framerate (optional)
+    }
+
+}
\ No newline at end of file

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Tue Mar 06 19:58:34 2012 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/4c0c40fd0593