refactor SPI handling and introduce SPI CS, forgotten files

game-ctrl/Makefile

@@ -11,7 +11,7 @@ CFLAGS=-Wall -mmcu=$(MCU) -std=gnu99 -I $(TOOLCHAIN_PREFIX)/include -O1 -g0
 
 LDFLAGS=-mmcu=$(MCU) -L $(TOOLCHAIN_PREFIX)/include
 
-$(ARTIFACT).elf:	main.o led.o scheduler.o canvas.o shapes.o game.o buttons.o myrand.o
+$(ARTIFACT).elf:	main.o spi.o scheduler.o canvas.o shapes.o game.o buttons.o myrand.o
 	$(CC) -o $@ $(LDFLAGS) $^
 	$(OBJDUMP) -D $(ARTIFACT).elf > $(ARTIFACT).txt
 

game-ctrl/buttons.c

@@ -6,8 +6,6 @@
 #include "scheduler.h"
 #include "shapes.h"
 #include "canvas.h"
-#include "led.h"
-
 
 
 static uint8_t buttonsMoveLeftPressed() {

game-ctrl/canvas.c

@@ -4,6 +4,7 @@
 #include <msp430g2553.h>
 
 #include "canvas.h"
+#include "spi.h"
 
 
 static uint8_t canvasStorage[CANVAS_WIDTH * CANVAS_HEIGHT];
@@ -20,17 +21,12 @@ const canvas_t miniCanvas = {
   .canvas = miniCanvasStorage
 };
 
-inline static void spiSendOctet(uint8_t v) {
-  // wait for TX buffer empty
-  while (!(UC0IFG & UCB0TXIFG));
-  // load octet into TX buffer
-  UCB0TXBUF = v;
-}
-
 void canvasShow() {
   // wait for signal waiting for data
   while (!(P1IN & BIT3));
 
+  spiSendBegin(e_SPI_CANVAS);
+
   for (uint8_t i = 0; i < (CANVAS_WIDTH*CANVAS_HEIGHT); i++) {
     if ((*((canvas.canvas)+i) & 0x80) != 0) {
       *((canvas.canvas)+i) &= ~0x80;
@@ -46,35 +42,14 @@ void canvasShow() {
     }
   }
   spiSendOctet(0xfe);
+
+  spiSendEnd(e_SPI_CANVAS);
 }
 
 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.
-  // 8 was still too fast and caused problems.
-  UCB0BR0 = 16; 
-  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();
   miniCanvasClear();
   canvasShow();

game-ctrl/main.c

@@ -5,12 +5,12 @@
 
 #include "time.h"
 #include "scheduler.h"
-#include "led.h"
 #include "canvas.h"
 #include "game.h"
 #include "buttons.h"
 #include "shapes.h"
 #include "myrand.h"
+#include "spi.h"
 
 
 int main() {
@@ -26,7 +26,7 @@ int main() {
 
     schInit();
 
-    ledInit();
+    spiInit();
     myRandInit();
     canvasInit();
 

game-ctrl/spi.c

@@ -0,0 +1,50 @@
+#include <msp430g2553.h>
+#include "spi.h"
+
+void spiInit() {
+  // 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.
+  // 8 was still too fast and caused problems.
+  UCB0BR0 = 16; 
+  UCB0BR1 = 0;
+
+  // BIT5: UCB0CLK
+  // BIT6: UCB0SOMI
+  // BIT7: UCB0SIMO
+  P1SEL |= BIT5 | BIT6 | BIT7;
+  P1SEL2 |= BIT5 | BIT6 | BIT7;
+  P1DIR |= BIT5 | BIT7;
+
+  // Device Select Lines: 0: Canvas, 1: Display, 2: Sound
+  P1DIR |= BIT0 | BIT1 | BIT2;
+  // Disable all of them
+  P1OUT |= BIT0 | BIT1 | BIT2;
+
+  // enable SPI module
+  UCB0CTL1 &= ~UCSWRST;
+}
+
+void spiSendBegin(t_SpiDeviceSelector d) {
+  uint16_t bit = ((uint16_t[]){ BIT0, BIT1, BIT2 })[d];
+  P1OUT &= ~bit;
+}
+
+void spiSendEnd(t_SpiDeviceSelector d) {
+  while (UCB0STAT & UCBUSY);
+  uint16_t bit = ((uint16_t[]){ BIT0, BIT1, BIT2 })[d];
+  P1OUT |= bit;
+}
+
+void spiSendOctet(uint8_t v) {
+  // wait for TX buffer empty
+  while (!(UC0IFG & UCB0TXIFG));
+  // load octet into TX buffer
+  UCB0TXBUF = v;
+}
+

game-ctrl/spi.h

@@ -0,0 +1,16 @@
+#ifndef _SPI_H_
+#define _SPI_H_
+
+#include <stdint.h>
+
+
+typedef enum { e_SPI_CANVAS, e_SPI_DISPLAY, e_SPI_SOUND } t_SpiDeviceSelector;
+
+void spiInit();
+void spiSendBegin(t_SpiDeviceSelector d);
+void spiSendEnd(t_SpiDeviceSelector d);
+void spiSendOctet(uint8_t v); 
+
+
+
+#endif // _SPI_H_

rgb-driver/main.S

@@ -96,11 +96,12 @@ init:
   ;; BIT3: Signal waiting for data
   mov.b   #BIT0|BIT1|BIT2|BIT3, &P1DIR
   mov.b   #0,&P1OUT
+  ;; BIT4: spi, UCB0STE
   ;; BIT5: spi, UCB0CLK
   ;; BIT6: spi, UCB0SOMI
   ;; BIT7: spi, UCB0SIMO
-  mov.b   #BIT5|BIT6|BIT7, &P1SEL
-  mov.b   #BIT5|BIT6|BIT7, &P1SEL2
+  mov.b   #BIT4|BIT5|BIT6|BIT7, &P1SEL
+  mov.b   #BIT4|BIT5|BIT6|BIT7, &P1SEL2
   ;; BIT4: long pulse
   ;; BIT1: short pulse
   mov.b   #BIT1|BIT4,&P2DIR
@@ -122,7 +123,7 @@ init:
 
   ;; spi configuration
   ;;  USCI B to slave mode
-  mov.b   #UCSYNC, &UCB0CTL0
+  mov.b   #UCSYNC|UCMODE_2, &UCB0CTL0
   mov.b   #0x00, &UCB0CTL1
 
   ;; make sure the isr will not immediately start