Trinket, Gemma & Due support (experimental)

Adafruit_WS2801.cpp

@@ -1,10 +1,50 @@
-#include "SPI.h"
 #include "Adafruit_WS2801.h"
 
 // Example to control WS2801-based RGB LED Modules in a strand or strip
 // Written by Adafruit - MIT license
 /*****************************************************************************/
 
+#ifdef __AVR_ATtiny85__
+
+// Teensy/Gemma-specific stuff for hardware-assisted SPI @ 1 MHz
+
+#if(F_CPU > 8000000L)
+  #define SPI_DELAY asm volatile("rjmp .+0\nrjmp .+0"); // Burn 4 cycles
+#elif(F_CPU > 4000000L)
+  #define SPI_DELAY asm volatile("rjmp .+0");           // Burn 2 cycles
+#else
+  #define SPI_DELAY                                     // Run max speed
+#endif
+
+#define SPIBIT                                  \
+  USICR = ((1<<USIWM0)|(1<<USITC));             \
+  SPI_DELAY                                     \
+  USICR = ((1<<USIWM0)|(1<<USITC)|(1<<USICLK)); \
+  SPI_DELAY
+
+static void spi_out(uint8_t n) {
+  USIDR = n;
+  SPIBIT
+  SPIBIT
+  SPIBIT
+  SPIBIT
+  SPIBIT
+  SPIBIT
+  SPIBIT
+  SPIBIT
+}
+
+#else
+
+// All other boards support Full and Proper Hardware SPI
+
+#include <SPI.h>
+#define spi_out(n) (void)SPI.transfer(n)
+
+#endif
+
+/*****************************************************************************/
+
 // Constructor for use with hardware SPI (specific clock/data pins):
 Adafruit_WS2801::Adafruit_WS2801(uint16_t n, uint8_t order) {
   rgb_order = order;
@@ -19,14 +59,15 @@ Adafruit_WS2801::Adafruit_WS2801(uint16_t n, uint8_t dpin, uint8_t cpin, uint8_t
   updatePins(dpin, cpin);
 }
 
-// Constructor for use with a matrix configuration, specify w, h for size of matrix
-// assumes configuration where string starts at coordinate 0,0 and continues to w-1,0, w-1,1
-// and on to 0,1, 0,2 and on to w-1,2 and so on. Snaking back and forth till the end.
-// other function calls with provide access to pixels via an x,y coordinate system
+// Constructor for use with a matrix configuration, specify w, h for size
+// of matrix.  Assumes configuration where string starts at coordinate 0,0
+// and continues to w-1,0, w-1,1 and on to 0,1, 0,2 and on to w-1,2 and
+// so on. Snaking back and forth till the end.  Other function calls
+// provide access to pixels via an x,y coordinate system
 Adafruit_WS2801::Adafruit_WS2801(uint16_t w, uint16_t h, uint8_t dpin, uint8_t cpin, uint8_t order) {
   rgb_order = order;
   alloc(w * h);
-  width = w;
+  width  = w;
   height = h;
   updatePins(dpin, cpin);
 }
@@ -53,9 +94,7 @@ Adafruit_WS2801::Adafruit_WS2801(void) {
 
 // Release memory (as needed):
 Adafruit_WS2801::~Adafruit_WS2801(void) {
-  if (pixels != NULL) {
-    free(pixels);
-  }
+  if(pixels) free(pixels);
 }
 
 // Activate hard/soft SPI as appropriate:
@@ -71,45 +110,59 @@ void Adafruit_WS2801::begin(void) {
 
 // Change pin assignments post-constructor, switching to hardware SPI:
 void Adafruit_WS2801::updatePins(void) {
-  hardwareSPI = true;
+  pinMode(datapin, INPUT); // Restore data and clock pins to inputs
+  pinMode(clkpin , INPUT);
   datapin     = clkpin = 0;
+  hardwareSPI = true;
   // If begin() was previously invoked, init the SPI hardware now:
   if(begun == true) startSPI();
   // Otherwise, SPI is NOT initted until begin() is explicitly called.
-
-  // Note: any prior clock/data pin directions are left as-is and are
-  // NOT restored as inputs!
 }
 
 // Change pin assignments post-constructor, using arbitrary pins:
 void Adafruit_WS2801::updatePins(uint8_t dpin, uint8_t cpin) {
-
   if(begun == true) { // If begin() was previously invoked...
     // If previously using hardware SPI, turn that off:
-    if(hardwareSPI == true) SPI.end();
-    // Regardless, now enable output on 'soft' SPI pins:
-    pinMode(dpin, OUTPUT);
+    if(hardwareSPI) {
+#ifdef __AVR_ATtiny85__
+      DDRB &= ~(_BV(PORTB1) | _BV(PORTB2));
+#else
+      SPI.end();
+#endif
+    } else {
+      pinMode(datapin, INPUT); // Restore prior data and clock pins to inputs
+      pinMode(clkpin , INPUT);
+    }
+    pinMode(dpin, OUTPUT); // Enable output on 'soft' SPI pins:
     pinMode(cpin, OUTPUT);
-  } // Otherwise, pins are not set to outputs until begin() is called.
-
-  // Note: any prior clock/data pin directions are left as-is and are
-  // NOT restored as inputs!
+  }
 
-  hardwareSPI = false;
   datapin     = dpin;
   clkpin      = cpin;
+#ifdef __AVR__
   clkport     = portOutputRegister(digitalPinToPort(cpin));
   clkpinmask  = digitalPinToBitMask(cpin);
   dataport    = portOutputRegister(digitalPinToPort(dpin));
   datapinmask = digitalPinToBitMask(dpin);
+#endif
+  hardwareSPI = false;
 }
 
 // Enable SPI hardware and set up protocol details:
 void Adafruit_WS2801::startSPI(void) {
-    SPI.begin();
-    SPI.setBitOrder(MSBFIRST);
-    SPI.setDataMode(SPI_MODE0);
-    SPI.setClockDivider(SPI_CLOCK_DIV16); // 1 MHz max, else flicker
+#ifdef __AVR_ATtiny85__
+  PORTB &= ~(_BV(PORTB1) | _BV(PORTB2)); // Outputs
+  DDRB  |=   _BV(PORTB1) | _BV(PORTB2);  // DO (NOT MOSI) + SCK
+#else
+  SPI.begin();
+  SPI.setBitOrder(MSBFIRST);
+  SPI.setDataMode(SPI_MODE0);
+ #if defined(__AVR__) || defined(CORE_TEENSY)
+  SPI.setClockDivider(SPI_CLOCK_DIV16); // 1MHz max, else flicker
+ #else
+  SPI.setClockDivider((F_CPU + 500000L) / 1000000L);
+ #endif
+#endif
 }
 
 uint16_t Adafruit_WS2801::numPixels(void) {
@@ -137,17 +190,21 @@ void Adafruit_WS2801::show(void) {
 
   // Write 24 bits per pixel:
   if(hardwareSPI) {
-    for(i=0; i<nl3; i++) {
-      SPDR = pixels[i];
-      while(!(SPSR & (1<<SPIF)));
-    }
+    for(i=0; i<nl3; i++) spi_out(pixels[i]);
   } else {
     for(i=0; i<nl3; i++ ) {
       for(bit=0x80; bit; bit >>= 1) {
+#ifdef __AVR__
         if(pixels[i] & bit) *dataport |=  datapinmask;
         else                *dataport &= ~datapinmask;
         *clkport |=  clkpinmask;
         *clkport &= ~clkpinmask;
+#else
+        if(pixels[i] & bit) digitalWrite(datapin, HIGH);
+        else                digitalWrite(datapin, LOW);
+        digitalWrite(clkpin, HIGH);
+        digitalWrite(clkpin, LOW);
+#endif
       }
     }
   }

Adafruit_WS2801.h

@@ -55,10 +55,13 @@ class Adafruit_WS2801 {
   uint8_t
     *pixels,   // Holds color values for each LED (3 bytes each)
     rgb_order, // Color order; RGB vs GRB (or others, if needed in future)
-    clkpin    , datapin,     // Clock & data pin numbers
+    clkpin    , datapin;     // Clock & data pin numbers
+#ifdef __AVR__
+  uint8_t
     clkpinmask, datapinmask; // Clock & data PORT bitmasks
   volatile uint8_t
     *clkport  , *dataport;   // Clock & data PORT registers
+#endif
   void
     alloc(uint16_t n),
     startSPI(void);

examples/strandtest/strandtest.pde

@@ -1,5 +1,8 @@
-#include "SPI.h"
 #include "Adafruit_WS2801.h"
+#include "SPI.h" // Comment out this line if using Trinket or Gemma
+#ifdef __AVR_ATtiny85__
+ #include <avr/power.h>
+#endif
 
 /*****************************************************************************
 Example sketch for driving Adafruit WS2801 pixels!
@@ -50,7 +53,10 @@ Adafruit_WS2801 strip = Adafruit_WS2801(25, dataPin, clockPin);
 //Adafruit_WS2801 strip = Adafruit_WS2801(25, WS2801_GRB);
 
 void setup() {
-
+#if defined(__AVR_ATtiny85__) && (F_CPU == 16000000L)
+  clock_prescale_set(clock_div_1); // Enable 16 MHz on Trinket
+#endif
+
   strip.begin();
 
   // Update LED contents, to start they are all 'off'