Diff: RA8875.cpp

Revision:

106:c80828f5dea4

Parent:

105:4f116006ba1f

Child:

107:f9ccffcb84f1

--- a/RA8875.cpp	Sat Feb 27 18:40:35 2016 +0000
+++ b/RA8875.cpp	Sat Feb 27 22:27:49 2016 +0000
@@ -216,7 +216,7 @@
 {
     unsigned char mwcr1 = ReadCommand(0x41) & ~0x01; // retain all but the currently selected layer
 
-    if (screenwidth >= 800 && screenheight >= 480 && screenbpp == 8) {
+    if (screenwidth >= 800 && screenheight >= 480 && screenbpp > 8) {
         return bad_parameter;
     } else if (layer > 1) {
         return bad_parameter;
@@ -568,6 +568,10 @@
         return false;
 }
 
+// RRRR RGGG GGGB BBBB
+// 4321 0543 2104 3210
+//           RRRG GGBB
+//           2102 1010
 uint8_t RA8875::_cvt16to8(color_t c16)
 {
     return ((c16 >> 8) & 0xE0)
@@ -575,15 +579,23 @@
         | ((c16 >> 3) & 0x03);
 }
 
+//           RRRG GGBB
+//           2102 1010
+// RRRR RGGG GGGB BBBB
+// 2101 0543 2104 3210
 color_t RA8875::_cvt8to16(uint8_t c8)
 {
-    color_t c16 = ((c8 & 0xE0) << 8)
-        | ((c8 & 0xC0) << 5)
-        | ((c8 & 0x1C) << 6)
-        | ((c8 & 0x1C) << 3)
-        | ((c8 & 0x03) << 3)
-        | ((c8 & 0x03) << 1)
-        | ((c8 & 0x03) >> 1);
+    color_t c16;
+    color_t temp = (color_t)c8;
+    
+    c16 = ((temp & 0xE0) << 8)
+        | ((temp & 0xC0) << 5)
+        | ((temp & 0x1C) << 6)
+        | ((temp & 0x1C) << 3)
+        | ((temp & 0x03) << 3)
+        | ((temp & 0x03) << 1)
+        | ((temp & 0x03) >> 1);
+    c16 = (c16 << 8) | (c16 >> 8);
     return c16;
 }
 
@@ -1115,7 +1127,8 @@
     _select(true);
     _spiwrite(0x40);         // Cmd: read data
     _spiwrite(0x00);         // dummy read
-    _spiwrite(0x00);         // dummy read  [20150201: Required to properly align the data stream. Not yet sure why...]
+    if (screenbpp == 16)
+        _spiwrite(0x00);     // dummy read is only necessary when in 16-bit mode
     while (count--) {
         if (screenbpp == 16) {
             pixel  = _spiread();
@@ -2866,4 +2879,3 @@
 }
 
 #endif // TESTENABLE
-