First draft of neopixel

libs/microbit/buffer.cpp

@@ -12,6 +12,11 @@ namespace BufferMethods {
         ManagedBuffer(buf).setByte(off, v);
     }
 
+    //%
+    uint8_t *getBytes(Buffer buf) {
+        return buf->payload;
+    }
+
     /** Returns the length of a Buffer object. */
     //% property
     int length(Buffer s) {

libs/neopixel/kind.json

@@ -0,0 +1,20 @@
+{
+    "name": "neppixel",
+    "description": "AdaFruit NeoPixel driver for micro:bit",
+    "files": [
+        "neopixel.ts",
+        "sendbuffer.asm"
+    ],
+    "testFiles": [
+        "neotest.ts"
+    ],
+    "microbit": {
+        "config": {
+            "MICROBIT_BLE_ENABLED": "0"
+        }
+    },
+    "public": true,
+    "dependencies": {
+        "microbit": "file:../microbit"
+    }
+}

libs/neopixel/neopixel.ts

@@ -0,0 +1,88 @@
+namespace neopixel {
+
+    //% shim=sendBufferAsm
+    function sendBuffer(buf: Buffer, pin: DigitalPin) {
+    }
+
+    class Strip {
+        buf: Buffer;
+        pin: DigitalPin;
+        brightness: number;
+
+        length() {
+            return this.buf.length / 3
+        }
+
+        /**
+         * Set the brightness of the strip, 0-255.
+         */
+        setBrigthness(brightness: number): void {
+            this.brightness = brightness;
+        }
+
+        /**
+         * Set the pin where the neopixel is connected, defaults to P0.
+         */
+        setPin(pin: DigitalPin): void {
+            this.pin = pin;
+            pins.digitalWritePin(this.pin, 0)
+            basic.pause(50)
+        }
+
+        /**
+         * Turn off all LEDs.
+         */
+        clear(): void {
+            this.buf.fill(0);
+        }
+
+        /**
+         * Shift LEDs forward.
+         */
+        shift(off: number): void {
+            this.buf.shift(-off * 3)
+        }
+
+        /**
+         * Shift LEDs forward.
+         */
+        rotate(): void {
+            this.buf.rotate(-3)
+        }
+
+        display() {
+            basic.pause(1)
+            sendBuffer(this.buf, this.pin);
+        }
+
+        /**
+         * Set give LED to a given color (range 0-255 for r, g, b)
+         */
+        setPix(ledoff: number, r: number, g: number, b: number): void {
+            ledoff = ledoff * 3;
+            let br = this.brightness;
+            if (br < 255) {
+                r = (Math.clamp(0, 255, r) * br) >> 8;
+                g = (Math.clamp(0, 255, b) * br) >> 8;
+                b = (Math.clamp(0, 255, b) * br) >> 8;
+            }
+            let buf = this.buf;
+            buf[ledoff + 0] = Math.clamp(0, 255, g);
+            buf[ledoff + 1] = Math.clamp(0, 255, r);
+            buf[ledoff + 2] = Math.clamp(0, 255, b);
+        }
+    }
+
+    /**
+     * Create a new NeoPixel driver for `numleds` LEDs.
+     * @params numleds number of leds in the strip, eg: 24,30,60,64
+     */
+    export function create(numleds: number): Strip {
+        let strip = new Strip();
+        strip.buf = pins.createBuffer(numleds * 3);
+        strip.setBrigthness(255)
+        strip.setPin(DigitalPin.P0)
+        return strip;
+    }
+
+}

libs/neopixel/neotest.ts

@@ -0,0 +1,92 @@
+basic.showLeds(`
+    # . . . .
+    . . . . .
+    . . # . .
+    . . . . .
+    . . . . #
+    `)
+console.log("Start")
+
+// Create a NeoPixel driver - specify the number of LEDs:
+let strip = neopixel.create(24);
+
+// If your strip is not at P0, specify the pin.
+strip.setPin(DigitalPin.P0)
+
+// Brightness defaults to 255 (very bright); 0 is completely off.
+strip.setBrigthness(20)
+
+// Set pixels - pixel number, followed by red, green and blue values, between 0 and 255.
+strip.setPix(0, 255, 255, 255);
+strip.setPix(1, 0, 255, 255);
+strip.setPix(2, 255, 0, 255);
+strip.setPix(3, 255, 255, 0);
+
+console.log("Send!")
+
+// Send the image to the strip.
+strip.display();
+basic.pause(500);
+
+console.log("Sent!")
+
+// Green light travelling the strip:
+for (let l = 0; l < strip.length(); l++) {
+    strip.clear();
+    strip.setPix(l, 0, 255, 0);
+    strip.display();
+    basic.pause(100);
+}
+
+let special = false;
+let numcol = 0;
+input.onButtonPressed(Button.A, () => {
+    special = true;
+    let r = 0;
+    let g = 0;
+    let b = 0;
+    if (numcol == 0) {
+        r = 255;
+        g = 255;
+        b = 255;
+    } else if (numcol == 1) {
+        r = 255;
+    } else if (numcol == 2) {
+        b = 255;
+    } else if (numcol == 3) {
+        r = 255;
+        g = 255;
+    } else if (numcol == 4) {
+        r = 10;
+        g = 10;
+        b = 10;
+    }
+    numcol = (numcol + 1) % 5;
+    for (let k = 0; k < 7; k++) {
+        strip.setPix(k, r, g, b);
+    }
+    strip.display();
+});
+
+control.inBackground(() => {
+    for (let j = 0; j < 2000000; j++) {
+        if (special) {
+            basic.pause(100);
+            continue;
+        }
+        let r1 = (0 + j * 2) & 63;
+        let g1 = (20 + j * 1) & 63;
+        let b1 = (30 + j * 3) & 63;
+        for (let i = 0; i < strip.length(); i++) {
+            strip.setPix(i, (r1 - i) * 20, (g1 - i) * 20, (b1 - i) * 20);
+        }
+        strip.display()
+        basic.pause(60);
+    }
+});
+
+control.inBackground(() => {
+    while (true) {
+        basic.showString("XMAS!", 150);
+    }
+});

libs/neopixel/sendbuffer.asm

@@ -0,0 +1,62 @@
+    push {r4,r5,r6,r7,lr}
+    
+    mov r4, r0 ; save buff
+    mov r6, r1 ; save pin
+    
+    mov r0, r4
+    bl buffer::count
+    mov r5, r0
+    
+    mov r0, r4
+    bl buffer::cptr
+    mov r4, r0
+    
+    ; setup pin as digital
+    mov r0, r6
+    movs r1, #0
+    bl micro_bit::digitalWritePin
+    
+    ; load pin address
+    mov r0, r6
+
+    ldr r0, [r0, #8] ; get mbed DigitalOut from MicroBitPin
+    ldr r1, [r0, #4] ; r1-mask for this pin
+    ldr r2, [r0, #16] ; r2-clraddr
+    ldr r3, [r0, #12] ; r3-setaddr
+    
+    cpsid i ; disable irq
+    
+    b .start
+    
+.nextbit:               ;            C0
+    str r1, [r3, #0]    ; pin := hi  C2
+    tst r6, r0          ;            C3
+    bne .islate         ;            C4
+    str r1, [r2, #0]    ; pin := lo  C6
+.islate:
+    lsrs r6, r6, #1     ; r6 >>= 1   C7
+    bne .justbit        ;            C8
+    
+    ; not just a bit - need new byte
+    adds r4, #1         ; r4++       C9
+    subs r5, #1         ; r5--       C10
+    bcc .stop           ; if (r5<0) goto .stop  C11
+.start:
+    movs r6, #0x80      ; reset mask C12
+    nop                 ;            C13
+
+.common:               ;             C13
+    str r1, [r2, #0]   ; pin := lo   C15
+    ; always re-load byte - it just fits with the cycles better this way
+    ldrb r0, [r4, #0]  ; r0 := *r4   C17
+    b .nextbit         ;             C20
+
+.justbit: ; C10
+    ; no nops, branch taken is already 3 cycles
+    b .common ; C13
+
+.stop:    
+    str r1, [r2, #0]   ; pin := lo
+    cpsie i            ; enable irq
+
+    pop {r4,r5,r6,r7,pc}