Tweak pushColors() for SAMD51, add non-DMA option to wobble example

Adafruit_TFTLCD.cpp

@@ -875,7 +875,11 @@ void Adafruit_TFTLCD::drawPixel(int16_t x, int16_t y, uint16_t color) {
 // externally by BMP examples.  Assumes that setWindowAddr() has
 // previously been set to define the bounds.  Max 255 pixels at
 // a time (BMP examples read in small chunks due to limited RAM).
+#if defined(__SAMD51__)
+void Adafruit_TFTLCD::pushColors(uint16_t *data, uint16_t len, boolean first) {
+#else
 void Adafruit_TFTLCD::pushColors(uint16_t *data, uint8_t len, boolean first) {
+#endif
   uint16_t color;
   uint8_t  hi, lo;
   CS_ACTIVE;

Adafruit_TFTLCD.h

@@ -38,7 +38,11 @@ class Adafruit_TFTLCD : public Adafruit_GFX {
   void     setRotation(uint8_t x);
        // These methods are public in order for BMP examples to work:
   void     setAddrWindow(int x1, int y1, int x2, int y2);
+#if defined(__SAMD51__)
+  void     pushColors(uint16_t *data, uint16_t len, boolean first);
+#else
   void     pushColors(uint16_t *data, uint8_t len, boolean first);
+#endif
   void     pushColorsDMA(uint32_t totalBytes, uint8_t *buffer,
              uint16_t bufSize, void (*callback)(uint8_t *dest, uint16_t len));
 

examples/wobble/wobble/wobble.ino

@@ -9,6 +9,8 @@
 
 #define LCD_RESET A4 // Alternately just connect to Arduino's reset pin
 
+#define DMA_SELECT A1 // Hi/lo chooses DMA vs non-DMA effect
+
 Adafruit_TFTLCD tft(LCD_CS, LCD_CD, LCD_WR, LCD_RD, LCD_RESET);
 
 #define DMALINES 16
@@ -23,6 +25,8 @@ void setup()
   Serial.begin(9600);
   while(!Serial);
 
+  pinMode(DMA_SELECT, INPUT_PULLUP);
+
   // Initialize pixel buffer with alternating red and white bands,
   // 32 pixels wide.  0x00F8 is 16-bit red (0xF800) endian-swapped
   // so bytes can be copied directly to screen.
@@ -62,7 +66,7 @@ void setup()
 int lineNum;
 int frame = 0;
 
-// pushColorsDMA() callback function -- fills one scanline with
+// pushColorsDMA() callback function -- fills DMALINES scanlines with
 // data from pixels[] array.
 void myCallback(uint8_t *dest, uint16_t len) {
   for(int i=0; i<DMALINES; i++) {
@@ -72,14 +76,25 @@ void myCallback(uint8_t *dest, uint16_t len) {
     if((lineNum + frame/8) & 32) offset = (offset + 32) % 63;
     memcpy(dest, &pixels[offset], len / DMALINES);
     lineNum++;
-    dest += 320 * 2; // Next scanline
+    dest += 320 * 2; // Offset to next scanline (2 bytes/pixel)
   }
 }
 
 void loop() {
   tft.setAddrWindow(0, 0, tft.width() - 1, tft.height() - 1);
   lineNum = 0;
-  tft.pushColorsDMA(tft.width() * tft.height() * 2, dmabuf, tft.width() * DMALINES * 2, myCallback);
+  if(digitalRead(DMA_SELECT)) {
+    tft.pushColorsDMA(tft.width() * tft.height() * 2, dmabuf, tft.width() * DMALINES * 2, myCallback);
+  } else {
+    bool first = true;
+    while(lineNum < tft.height()) {
+      // Fill the DMA buffer, but don't issue it
+      myCallback(dmabuf, tft.width() * DMALINES * 2);
+      // Then send it using non-DMA function:
+      tft.pushColors((uint16_t *)dmabuf, tft.width() * DMALINES, first);
+      first = false;
+    }
+  }
   frame++;
   uint32_t elapsed = (millis() - startTime) / 1000;
   if(elapsed > 0) {