image

main.S

@@ -9,12 +9,12 @@
 ;; ----------------------------------------------------
 ;; --- r4, r5 and r6 must not be used for any other ---
 ;; --- purpose                                      ---
-;; required for communication between drawscreen and shifter isr
+;; required for communication between drawscreen and isr
 #define SIGNAL_REGISTER r4
-#define SIGNAL_INIT_VALUE SIGNAL_OCTET_DONE
 #define SIGNAL_OCTET_DONE 0x01
 #define SIGNAL_ISR_ENABLE 0x02
 #define SIGNAL_ALL_DATA_DONE 0x04
+#define SIGNAL_INIT_VALUE SIGNAL_OCTET_DONE
 
 ;; required for handover of data between drawscreen and isr
 #define DATA_REGISTER r5
@@ -101,10 +101,10 @@ init:
   ;; BIT7: spi, UCB0SIMO
   mov.b   #BIT5|BIT6|BIT7, &P1SEL
   mov.b   #BIT5|BIT6|BIT7, &P1SEL2
-  ;; BIT1: timer, short pulse
-  ;; BIT4: timer, long pulse
-  mov.b   #BIT1|BIT4, &P2DIR
-  mov.b   #BIT1|BIT4, &P2SEL
+  ;; BIT4: long pulse
+  ;; BIT1: short pulse
+  mov.b   #BIT1|BIT4,&P2DIR
+  mov.b   #BIT1|BIT4,&P2SEL
 
   ;; timer configuration
   ;;  configure and stop timer
@@ -122,7 +122,7 @@ init:
 
   ;; spi configuration
   ;;  USCI B to slave mode
-  mov.b   #0x00, &UCB0CTL0
+  mov.b   #UCSYNC, &UCB0CTL0
   mov.b   #0x00, &UCB0CTL1
 
   ;; make sure the isr will not immediately start
@@ -136,7 +136,7 @@ init:
 
 ;; ----------------------------------------------------
 mainloop:
-  ;call    #forwardscreen_init
+  call    #forwardscreen_init
   call    #resetscreen
 
 mainloop_draw:
@@ -145,16 +145,13 @@ mainloop_draw:
   ;; signal waiting for data
   set_signal_waiting_for_data
 
-  call    #forwardscreen
-  call    #wait
-
-  ;; receive data via spi
-  ;call    #receivedata
+  ;call    #forwardscreen
+  ;call    #wait
+  call    #receivedata
 
   ;; data has been received, clear signal
   clear_signal_waiting_for_data
 
-
   jmp     mainloop_draw
 
 
@@ -163,7 +160,7 @@ wait:
   push    r11
   push    r12
 
-  mov.w   #0x0010, r11
+  mov.w   #0x0040, r11
 wait_continue_1:
   mov.w   #0xffff, r12
 wait_continue_2:
@@ -191,7 +188,7 @@ forwardscreen:
   mov.w   data_forward_pointer, r10
   mov.b   #_off, @r10
   inc.w   r10
-  mov.b   #_white, @r10
+  mov.b   #_blue, @r10
   cmp.w   r10, r8
   jnz     forwardscreen_done
   mov.w   #screendata, r10
@@ -224,65 +221,48 @@ resetscreen_continue:
 
 ;; ----------------------------------------------------
 receivedata:
-  push    r7
-  push    r8
   push    r9
   push    r10
 
-  ;; screendata addresses
-  mov.w   #screendata, r7
-  mov.w   #screendataend, r8
- 
   ;; wait for first octet
-receivedata_wait_for_first_octet:
+receivedata_wait_for_control_octet:
   bit     #UCB0RXIFG, &UC0IFG
-  jz      receivedata_wait_for_first_octet
+  jz      receivedata_wait_for_control_octet
 
-  ;; get data from buffer register
+  ;; get control or address octet from buffer register
   mov.b   UCB0RXBUF, r9
-
-  ;; check whether value == 0xff (wait for the whole 
+  ;; check whether value == 0xff (wait for the whole
   ;; set of data to fill the screendata)
   cmp.b   #0xff, r9
-
-  ;; receive all data 
+  ;; receive all data
   jz      receivedata_wait_for_all_data
+  ;; check whether value == 0xfe (no more data)
+  cmp.b   #0xfe, r9
+  ;; no more data
+  jz      receivedata_end
 
-  ;; if it is not 0xff, it is the octet number which is the
-  ;; relative address within screendata
+  ;; it is an address octet
 receivedata_wait_for_octet:
   bit     #UCB0RXIFG, &UC0IFG
   jz      receivedata_wait_for_octet
 
-  ;; get octet from buffer register
+  ;; get data octet from buffer register
   mov.b   UCB0RXBUF, r10
-
   ;; move it to the destination
-  mov.b   r10, screendata(r9) 
-  
-  ;; done
-  jmp     receivedata_end
+  mov.b   r10, screendata(r9)
+  ;; next address/control octet
+  jmp     receivedata_wait_for_control_octet
 
 receivedata_wait_for_all_data:
   ;; this is a bit dangerous, if the application controller
   ;; sends too few data, we are in a dead lock
 
-
-
-
-
 receivedata_end:
   pop     r10
   pop     r9
-  pop     r8
-  pop     r7
   ret
 
 
-
-
-
-
 ;; ----------------------------------------------------
 drawscreen:
   push    r7
@@ -360,26 +340,26 @@ drawscreen_data_done:
 ;; ----------------------------------------------------
 ; --- timer isr ---
   ;; r6: exclusively used by isr as bit-counter
-shifter_isr:
+timer1_a0_isr:
   ;; check isr enable bit
   bit     #SIGNAL_ISR_ENABLE, SIGNAL_REGISTER
-  jz      shifter_isr_exit
+  jz      timer1_a0_isr_exit
 
   ;; shift msb of data register r5 into carry flag and set or reset P1.0 accordingly
   rla.b   DATA_REGISTER
-  jnc     shifter_isr_false_bit
+  jnc     timer1_a0_isr_false_bit
   set_data_bit
-  jmp     shifter_isr_end
-shifter_isr_false_bit:
+  jmp     timer1_a0_isr_end
+timer1_a0_isr_false_bit:
   clear_data_bit
    
-shifter_isr_end:
+timer1_a0_isr_end:
   ;; enable output
   set_output_enable
 
   ;; roll bit-counter
   rla.b   BIT_COUNTER_REGISTER
-  jnc     shifter_isr_exit
+  jnc     timer1_a0_isr_exit
 
   ;; reset bit-counter
   mov.b   #BIT_COUNTER_INIT_VALUE, BIT_COUNTER_REGISTER
@@ -388,19 +368,19 @@ shifter_isr_end:
 
   ;; check whether all data are processed
   bit     #SIGNAL_ALL_DATA_DONE,  SIGNAL_REGISTER
-  jz      shifter_isr_exit
+  jz      timer1_a0_isr_exit
   ;; disable isr
   bic     #SIGNAL_ISR_ENABLE,  SIGNAL_REGISTER
   ;; disable output
   clear_output_enable
 
-shifter_isr_exit:
+timer1_a0_isr_exit:
   reti
 
 
 ;; ----------------------------------------------------
   .section "__interrupt_vector_14","ax",@progbits
-  .word   shifter_isr
+  .word   timer1_a0_isr
 
   ;; .resetvec comes from linker
   .section ".resetvec","ax",@progbits