changes

.gitignore

@@ -0,0 +1,3 @@
+*.o
+firmware.*
+

Makefile

@@ -6,13 +6,13 @@ MCU=msp430g2553
 ARTIFACT=firmware
 COMMON=-Wall -mmcu=$(MCU) -std=gnu99 -I $(TOOLCHAIN_PREFIX)/include -Os -g0 -fdata-sections -ffunction-sections
 CFLAGS=$(COMMON)
-ASFLAGS=$(COMMON)
+ASFLAGS=$(COMMON) -D__ASSEMBLER__
 
 LDFLAGS=-L $(TOOLCHAIN_PREFIX)/include -Wl,-Map,firmware.map -nostdlib -nostartfiles -T $(MCU).ld
 
 $(ARTIFACT).elf:	main.o
 	$(CC) -o $@ $(LDFLAGS) $^
-	$(OBJDUMP) -d $(ARTIFACT).elf > $(ARTIFACT).txt
+	$(OBJDUMP) -D $(ARTIFACT).elf > $(ARTIFACT).txt
   
 
 .c.o:	

main.S

@@ -8,13 +8,36 @@
 #define SR r2
 
 
+  .section ".rodata","a"
+screendatacnt:
+  .byte   0x01
+screendata:
+  .byte   0x00
+red:
+colors1:
+  .byte   0b01001111
+colors2:
+  .byte   0b01000111
+colors3:
+  .byte   0b01000011
+  .byte   0
+blue:
+  .byte   0b11001111
+  .byte   0b11000111
+  .byte   0b11000011
+  .byte   0
+green:
+  .byte   0b10001111
+  .byte   0b10000111
+  .byte   0b10000011
+  .byte   0
+
   ;; .text is the name of the section, it is a hint for the linker to
   ;; allocate the section
   ;; ax: a means allocatable by linker, x means executable
   ;; @progbits is a hint for the linker to allocate this section into
   ;; program memory (flash)
   .section ".text","ax",@progbits
-
 _start:
   ;; disable watchdog
   mov.w   #WDTPW|WDTHOLD,&WDTCTL
@@ -29,45 +52,99 @@ _start:
   mov.w   #__stack, SP
 
 init:
-  ;; configuration of GPIO Port1, use Bit6 as TA0.1
-  mov.b   #BIT6,&P1DIR
-  mov.b   #BIT6,&P1SEL
+  ;; configuration of GPIO Ports
+  mov.b   #BIT0|BIT1|BIT2,&P1DIR
+  mov.b   #BIT1|BIT4,&P2DIR
+  mov.b   #BIT1|BIT4,&P2SEL
 
   ;; timer configuration
   ;;  configure and stop timer
   ;;  cycle time is 56.25ns
-  mov.w   #ID_0|MC_0|TACLR|TASSEL_2,&TACTL
+  mov.w   #ID_0|MC_0|TACLR|TASSEL_2,&TA1CTL
   ;;  2.0us 
-  mov.w   #45,&TACCR0
+  mov.w   #45,&TA1CCR0
   ;;  a bit less
-  mov.w   #16,&TACCR1
+  mov.w   #10,&TA1CCR1
+  mov.w   #22,&TA1CCR2
   ;;  configure output mode for TA0.1
-;  mov.w   #CCIE,&TACCTL0
-;  mov.w   #CCIE,&TACCTL1
-  mov.w   #OUTMOD_7,&TACCTL1
-  ;;  start timer in up mode
-  bis.w   #MC0,&TACTL
+  mov.w   #CCIE,&TA1CCTL0
+  mov.w   #OUTMOD_7,&TA1CCTL1
+  mov.w   #OUTMOD_7,&TA1CCTL2
 
+  ;; test data
+  mov.b   #0b01101111,r5
+  ;; initialize bit-counter for isr
+  mov.b   #0x01,r6
+  ;; initialize isr-sync register
+  mov.b   #0x00,r4
+
+  ;; start timer in up mode
+  bis.w   #MC0,&TA1CTL
   ;; enable interrupts
   eint
 
+  ;; r4: synchronization between mainloop and isr
+  ;; r5: data byte to be handled by isr
 mainloop:
+  ;; prepare next byte to handle by isr
+
+mainloop_wait_for_isr:
+  ;; check bit0 in sync register
+  bit     #0x01,r4
+  jz      mainloop_wait_for_isr
+
+  ;; load data
+  mov.b   #0b01001111,r5
+  mov.b   #0x00,r4
+  ;; signal reload
+  bis     #BIT2,&P1OUT
+  bic     #BIT2,&P1OUT
+
+  ;; continue
   jmp     mainloop
 
 ; --- timer isr ---
-;timer0_a0_isr:
-;  mov.b   #BIT0,&P1OUT
-;  reti
+  ;; r6: exclusively used by isr as bit-counter
+timer1_a0_isr:
+  ;; func begin marker
+  bis     #BIT0,&P1OUT
+  ;; check isr idle bit
+  bit     #BIT1,r4
+  jnz     timer1_a0_isr_exit
+
+  ;; shift msb of data register r5 into carry flag and set or reset P1.1 accordingly
+  rla.b   r5
+  jnc     timer1_a0_isr_false_bit
+  bis     #BIT1,&P1OUT
+  jmp     timer1_a0_isr_end
+timer1_a0_isr_false_bit:
+  bic     #BIT1,&P1OUT
+   
+  ;; shift bit-counter, after eight shifts signal byte done and reset bit-counter
+timer1_a0_isr_end:
+  rla.b   r6
+  jnc     timer1_a0_isr_exit
+
+  ;; reset bit-counter
+  mov.b   #0x01,r6
+  ;; signal byte done
+  mov.b   #0x01,r4
+
+timer1_a0_isr_exit:
+  ;; func end marker
+  bic     #BIT0,&P1OUT
+  reti
+
+
 
 ;timer0_a1_isr:
-;  mov.b   #0,&P1OUT
 ;  reti
 
 ; --- interrupt vectors ---
 ;  .section "__interrupt_vector_9","ax",@progbits
 ;  .word   timer0_a1_isr
-;  .section "__interrupt_vector_10","ax",@progbits
-;  .word   timer0_a0_isr
+  .section "__interrupt_vector_14","ax",@progbits
+  .word   timer1_a0_isr
 
   ;; .resetvec comes from linker
   .section ".resetvec","ax",@progbits