DV Display: Support multiple scroll offsets

drivers/dv_display/dv_display.cpp

@@ -119,7 +119,7 @@ namespace pimoroni {
     while (gpio_get(VSYNC) == 0);
     gpio_put(RAM_SEL, bank);
     if (rewrite_header) {
-      write_header();
+      set_scroll_idx_for_lines(-1, 0, display_height);
       rewrite_header = false;
     }
   }
@@ -128,9 +128,35 @@ namespace pimoroni {
     swd_reset();
   }
 
-  void DVDisplay::set_display_offset(const Point& p) {
+  void DVDisplay::set_display_offset(const Point& p, int idx) {
     int32_t offset = (int32_t)point_to_address(p) - (int32_t)point_to_address({0,0});
-    i2c->write_bytes(I2C_ADDR, I2C_REG_SCROLL, (uint8_t*)&offset, 4);
+    i2c->write_bytes(I2C_ADDR, I2C_REG_SCROLL_BASE + 4*(idx-1), (uint8_t*)&offset, 4);
+  }
+
+  void DVDisplay::set_scroll_idx_for_lines(int idx, int miny, int maxy) {
+    constexpr int buf_size = 32;
+    uint32_t buf[buf_size];
+    uint addr = 4 * (7 + miny);
+    uint line_type = (uint)mode << 28;
+    if (idx >= 0) line_type |= (uint)idx << 30;
+    for (int i = miny; i < maxy; i += buf_size) {
+      int maxj = std::min(buf_size, maxy - i);
+      if (idx >= 0) {
+        for (int j = 0; j < maxj; ++j) {
+          buf[j] = line_type + ((uint32_t)h_repeat << 24) + ((i + j) * frame_width * 6) + base_address;
+        }
+      }
+      else {
+        ram.read_blocking(addr, buf, maxj);
+        for (int j = 0; j < maxj; ++j) {
+          buf[j] &= 0xC0000000;
+          buf[j] |= line_type + ((uint32_t)h_repeat << 24) + ((i + j) * frame_width * 6) + base_address;
+        }
+      }
+      ram.write(addr, buf, maxj * 4);
+      ram.wait_for_finish_blocking();
+      addr += 4 * maxj;
+    }
   }
 
   uint8_t DVDisplay::get_gpio() {
@@ -294,7 +320,7 @@ namespace pimoroni {
   {
     mode = new_mode;
     rewrite_header = true;
-    write_header();
+    set_scroll_idx_for_lines(-1, 0, display_height);
     if (mode == MODE_PALETTE) {
       write_palette();
     }
@@ -381,19 +407,7 @@ namespace pimoroni {
   void DVDisplay::write_header()
   {
     write_header_preamble();
-
-    uint32_t buf[8];
-    uint addr = 4 * 7;
-    uint line_type = 0x80000000u + ((uint)mode << 28);
-    mp_printf(&mp_plat_print, "Write header, line type %08x\n", line_type);
-    for (int i = 0; i < display_height; i += 8) {
-      for (int j = 0; j < 8; ++j) {
-        buf[j] = line_type + ((uint32_t)h_repeat << 24) + ((i + j) * frame_width * 6) + base_address;
-      }
-      ram.write(addr, buf, 8 * 4);
-      ram.wait_for_finish_blocking();
-      addr += 4 * 8;
-    }
+    set_scroll_idx_for_lines(1, 0, display_height);
   }
 
   uint32_t DVDisplay::point_to_address(const Point& p) const {

drivers/dv_display/dv_display.hpp

@@ -31,8 +31,8 @@ namespace pimoroni {
 
     // I2C address and registers
     static constexpr uint I2C_ADDR = 0x0D;
-    static constexpr uint I2C_REG_SET_RES = 0xF8;
-    static constexpr uint I2C_REG_START = 0xF9;
+    static constexpr uint I2C_REG_SET_RES = 0xFC;
+    static constexpr uint I2C_REG_START = 0xFD;
     static constexpr uint I2C_REG_GPIO = 0xC0;
     static constexpr uint I2C_REG_LED = 0xC1;
     static constexpr uint I2C_REG_GPIO_HI = 0xC8;
@@ -41,7 +41,7 @@ namespace pimoroni {
     static constexpr uint I2C_REG_GPIO_HI_PULL_UP = 0xCB;
     static constexpr uint I2C_REG_GPIO_HI_PULL_DOWN = 0xCC;
     static constexpr uint I2C_REG_EDID = 0xED;
-    static constexpr uint I2C_REG_SCROLL = 0xF0;
+    static constexpr uint I2C_REG_SCROLL_BASE = 0xF0;
 
     //--------------------------------------------------
     // Variables
@@ -146,9 +146,14 @@ namespace pimoroni {
       void write_palette_pixel_span(const Point &p, uint l, uint8_t* data);
       void read_palette_pixel_span(const Point &p, uint l, uint8_t *data);
 
-      // Set the top left corner of the display within the frame, if a larger
-      // frame is specified than the display.
-      void set_display_offset(const Point& p);
+      // Set the scroll offset for a set of scanlines on the display.  There are 3 scroll offsets, indexes 1-3.
+      // By default, all scanlines are offset by scroll idx 1, so setting this effectively moves the 
+      // top left corner of the display within the frame.
+      void set_display_offset(const Point& p, int idx=1);
+
+      // Configure the scroll offset index to use for a set of scanlines (inclusive of miny, exclusive of maxy),
+      // this applies to the current bank only - you need to set again after flipping to apply the same setting to the other bank.
+      void set_scroll_idx_for_lines(int idx, int miny, int maxy);
 
       uint8_t get_gpio();
       uint8_t get_gpio_hi();

examples/dv_stick/dv_stick_test.cpp

@@ -13,7 +13,7 @@ using namespace pimoroni;
 #define DISPLAY_HEIGHT 480
 
 #define FRAME_WIDTH 1000
-#define FRAME_HEIGHT 480
+#define FRAME_HEIGHT 600
 
 #define READ_EDID 0
 #if READ_EDID
@@ -49,7 +49,7 @@ int main() {
   gpio_set_dir(BUTTON_A, GPIO_IN);
   gpio_pull_up(BUTTON_A);
 
-  //sleep_ms(5000);
+  sleep_ms(5000);
 
   DVDisplay display;
   display.init(DISPLAY_WIDTH, DISPLAY_HEIGHT, DVDisplay::MODE_RGB888, FRAME_WIDTH, FRAME_HEIGHT);
@@ -90,18 +90,23 @@ int main() {
   printf(".\n");
   graphics.clear();
   printf("..\n");
+  display.set_scroll_idx_for_lines(0, 100, 200);
+  display.set_scroll_idx_for_lines(2, 300, FRAME_HEIGHT);
   display.flip();
   printf("...\n");
   sleep_ms(2000);
   graphics.set_pen(0, 0, 0xFF);
   graphics.clear();
+  display.set_scroll_idx_for_lines(0, 100, 200);
+  display.set_scroll_idx_for_lines(2, 300, FRAME_HEIGHT);
   display.flip();
 
   printf("Starting\n");
   graphics.set_font("bitmap8");
 
-  Point scroll = {0, 0};
-  int scroll_dir = 1;
+  Point scroll1 = {0, 0};
+  Point scroll2 = {0, 0};
+  int scroll_dir[2] = {1,1};
 
   constexpr int NUM_CIRCLES = 50;
   struct Circle {
@@ -204,20 +209,18 @@ int main() {
 
     //printf("%02x %02x\n", display.get_gpio(), display.get_gpio_hi());
 
-    display.set_display_offset(scroll);
-    #if 1
-    scroll.x += scroll_dir;
-    if (scroll.x + DISPLAY_WIDTH > FRAME_WIDTH || scroll.x < 0) {
-      scroll_dir = -scroll_dir;
-      scroll.x += scroll_dir;
+    display.set_display_offset(scroll1, 1);
+    display.set_display_offset(scroll2, 2);
+    scroll1.x += scroll_dir[0];
+    if (scroll1.x + DISPLAY_WIDTH > FRAME_WIDTH || scroll1.x < 0) {
+      scroll_dir[0] = -scroll_dir[0];
+      scroll1.x += scroll_dir[0];
     }
-    #else
-    scroll.y += scroll_dir;
-    if (scroll.y + DISPLAY_HEIGHT > FRAME_HEIGHT || scroll.y < 0) {
-      scroll_dir = -scroll_dir;
-      scroll.y += scroll_dir;
+    scroll2.y += scroll_dir[1];
+    if (scroll2.y + DISPLAY_HEIGHT > FRAME_HEIGHT || scroll2.y < 0) {
+      scroll_dir[1] = -scroll_dir[1];
+      scroll2.y += scroll_dir[1];
     }
-    #endif
 
     ++frames;
     display.set_gpio_hi_pull_up_all(frames & 0x3F);