begin sound driver

sound-driver/Makefile

@@ -0,0 +1,31 @@
+TOOLCHAIN_PREFIX=/opt/msp430-gcc
+CC=$(TOOLCHAIN_PREFIX)/bin/msp430-elf-gcc
+OBJDUMP=$(TOOLCHAIN_PREFIX)/bin/msp430-elf-objdump
+
+ARTIFACT=firmware
+MCU=msp430g2553
+CFLAGS=-Wall -mmcu=$(MCU) -std=gnu99 -I $(TOOLCHAIN_PREFIX)/include -O1 -g0
+
+# for debugging
+#CFLAGS+= -g3 -ggdb -gdwarf-2
+
+LDFLAGS=-mmcu=$(MCU) -L $(TOOLCHAIN_PREFIX)/include
+
+$(ARTIFACT).elf:	main.o
+	$(CC) -o $@ $(LDFLAGS) $^
+	$(OBJDUMP) -D $(ARTIFACT).elf > $(ARTIFACT).txt
+
+.c.o:	
+	$(CC) $(CFLAGS) -c $<
+
+
+.PHONY: all
+all:	$(ARTIFACT).elf
+
+.PHONY: clean
+clean:
+	-rm -f *.o $(ARTIFACT).elf $(ARTIFACT).txt
+
+.PHONY: upload
+upload: $(ARTIFACT).elf
+	mspdebug rf2500 "prog $(ARTIFACT).elf"

sound-driver/main.c

@@ -0,0 +1,43 @@
+#include <msp430g2553.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+
+
+void __attribute__ ((interrupt (USCIAB0RX_VECTOR))) receive() {
+  if (UC0IFG & UCB0RXIFG) {
+    // receive an octet
+  }
+}
+
+
+int main() {
+  WDTCTL = WDTPW | WDTHOLD;
+
+  __disable_interrupt();
+
+  // highest possible system clock
+  DCOCTL = DCO0 | DCO1 | DCO2;
+  BCSCTL1 = XT2OFF | RSEL0 | RSEL1 | RSEL2 | RSEL3;
+  BCSCTL2 = 0;
+  BCSCTL3 = 0;
+
+  // SPI slave
+  // BIT4: UCB0STE
+  // BIT5: UCB0CLK
+  // BIT6: UCB0SOMI
+  // BIT7: UCB0SIMO
+  P1SEL |= BIT4 | BIT5 | BIT6 | BIT7;
+  P1SEL2 |= BIT4 | BIT5 | BIT6 | BIT7;
+  // most significant bit first, enable STE
+  UCB0CTL0 = UCSYNC | UCMSB | UCMODE_2;
+  UCB0CTL1 = 0x00;
+  // enable RX interrupt
+  UC0IE |= UCB0RXIE;
+
+
+  __enable_interrupt();
+
+  while (1) {
+  }
+}