code beautifying

game-ctrl/canvas.c

@@ -1,33 +1,76 @@
 #include <string.h>
 #include <stdint.h>
 
+#include <msp430g2553.h>
+
 #include "canvas.h"
-#include "displayDriver.h"
 
 
 static uint8_t canvasStorage[CANVAS_WIDTH * CANVAS_HEIGHT];
 const canvas_t canvas = { 
   .height = CANVAS_HEIGHT,
   .width = CANVAS_WIDTH,
-  .size = CANVAS_WIDTH * CANVAS_HEIGHT,
   .canvas = canvasStorage
 };
 
-void canvasInit() {
-  canvasClear();
-  displayDriverTransferCanvas();
-}
 
-void canvasClear() {
-  memset(canvas.canvas, 0x80, canvas.size);
-}
-
-void canvasSetAll(uint8_t color) {
-  memset(canvas.canvas, color + 0x80, canvas.size);
+inline static void spiSendOctet(uint8_t v) {
+  // wait for TX buffer empty
+  while (!(UC0IFG & UCB0TXIFG));
+  // load octet into TX buffer
+  UCB0TXBUF = v;
 }
 
 void canvasShow() {
-  displayDriverTransferCanvas();
+  // wait for signal waiting for data
+  while ((P1IN & BIT3) == 0);
+
+  for (uint8_t i = 0; i < (CANVAS_WIDTH*CANVAS_HEIGHT); i++) {
+    if ((*((canvas.canvas)+i) & 0x80) != 0) {
+      *((canvas.canvas)+i) &= ~0x80;
+      spiSendOctet(i);
+      spiSendOctet(*((canvas.canvas)+i));
+    }
+  }
+  spiSendOctet(0xfe);
+}
+
+void canvasInit() {
+  // SPI in master mode
+  UCB0CTL0 = UCMST;
+  // SPI timing config
+  UCB0CTL1 = UCSSEL_3;
+  // Faster than 8 ends up in strange communication errors
+  // between the both MCUs.
+  // With 8 the transfer of a complete 110 pixel canvas takes
+  // about 720us.
+  UCB0BR0 = 8; 
+  UCB0BR1 = 0;
+
+  // BIT5: UCB0CLK
+  // BIT6: UCB0SOMI
+  // BIT7: UCB0SIMO
+  P1SEL |= BIT5 | BIT6 | BIT7;
+  P1SEL2 |= BIT5 | BIT6 | BIT7;
+  P1DIR |= BIT5 | BIT7;
+
+  // P1.3 is signal line
+  P1DIR &= ~BIT3;
+
+  // enable SPI module
+  UCB0CTL1 &= ~UCSWRST;
+
+
+  canvasClear();
+  canvasShow();
+}
+
+void canvasClear() {
+  memset(canvas.canvas, 0x80, CANVAS_WIDTH*CANVAS_HEIGHT);
+}
+
+void canvasSetAll(uint8_t color) {
+  memset(canvas.canvas, color + 0x80, CANVAS_WIDTH*CANVAS_HEIGHT);
 }
 
 void canvasSetPixel(uint8_t column, uint8_t row, uint8_t color) {