image

Makefile

@@ -10,7 +10,7 @@ ASFLAGS=$(COMMON) -D__ASSEMBLER__
 
 LDFLAGS=-L $(TOOLCHAIN_PREFIX)/include -Wl,-Map,firmware.map -nostdlib -nostartfiles -T $(MCU).ld
 
-$(ARTIFACT).elf:	main.o
+$(ARTIFACT).elf:	colors.o main.o
 	$(CC) -o $@ $(LDFLAGS) $^
 	$(OBJDUMP) -D $(ARTIFACT).elf > $(ARTIFACT).txt
   

colors.S

@@ -0,0 +1,38 @@
+#include "colors.h"
+
+#define DIMM_FACTOR 3
+  .section ".rodata","a"
+;; color definitions according to
+;; https://learn.sparkfun.com/tutorials/lilypad-protosnap-plus-activity-guide/3-custom-color-mixing
+colors:
+  .global colors
+  ;;      red, green, blue, padding
+off:
+  .byte   0x00, 0x00, 0x00, 0
+blue:
+  .byte   0x00>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
+green:
+  .byte   0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
+orange:
+  .byte   0xff>>DIMM_FACTOR, 0x80>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
+rose:
+  .byte   0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0x80>>DIMM_FACTOR, 0
+magenta:
+  .byte   0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
+violet:
+  .byte   0x80>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
+azure:
+  .byte   0x00>>DIMM_FACTOR, 0x80>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
+cyan:
+  .byte   0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
+springgreen:
+  .byte   0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0x80>>DIMM_FACTOR, 0
+chartreuse:
+  .byte   0x80>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
+yellow:
+  .byte   0xff>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
+white:
+  .byte   0xff>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
+red:
+  .byte   0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
+

colors.h

@@ -0,0 +1,22 @@
+#ifndef _COLORS_H_
+#define _COLORS_H_
+
+
+#define _off 0x00
+#define _blue 0x01
+#define _green 0x02
+#define _orange 0x03
+#define _rose 0x04
+#define _magenta 0x05
+#define _violet 0x06
+#define _azure 0x07
+#define _cyan 0x08
+#define _springgreen 0x09
+#define _chartreuse 0x0a
+#define _yellow 0x0b
+#define _white 0x0c
+#define _red 0x0d
+
+
+
+#endif

main.S

@@ -1,39 +1,72 @@
-  .file "main.S"
-
 #include <msp430g2553.h>
-
+#include "colors.h"
 
 #define PC r0
 #define SP r1
 #define SR r2
 
 
-  .section ".rodata","a"
+;; ----------------------------------------------------
+;; --- r4, r5 and r6 must not be used for any other ---
+;; --- purpose                                      ---
+;; required for communication between drawscreen and isr
+#define SIGNAL_REGISTER r4
+#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
+
+;; required for sequencing of isr
+#define BIT_COUNTER_REGISTER r6
+#define BIT_COUNTER_INIT_VALUE 0x01
+;; ----------------------------------------------------
+
+
+;; 2.48us
+#define TIMER_COMPLETE 45
+;; 1.18us
+#define TIMER_LONG 22
+;; 550ns
+#define TIMER_SHORT 10
+
+  .macro set_data_bit
+  bis   #BIT0, &P1OUT
+  .endm
+  .macro clear_data_bit
+  bic   #BIT0, &P1OUT
+  .endm
+  .macro set_output_enable
+  bis   #BIT1, &P1OUT
+  .endm
+  .macro clear_output_enable
+  bic   #BIT1, &P1OUT
+  .endm
+  .macro set_debug
+  bis   #BIT2, &P1OUT
+  .endm
+  .macro clear_debug
+  bic   #BIT2, &P1OUT
+  .endm
+  .macro set_signal_waiting_for_data
+  bis   #BIT3, &P1OUT
+  .endm
+  .macro clear_signal_waiting_for_data
+  bic   #BIT3, &P1OUT
+  .endm
+
+  .section ".data"
 screendata:
-  .byte   0x01
+  .rept 60 ;; number of leds in hardward
-  .byte   0x03
+  .byte 0
-  .byte   0x07
+  .endr
-  .byte   0x0f
 screendataend:
-  .byte   0xff
+  .byte 0xff
-red:
+data_forward_pointer:
-colors1:
+  .word 0
-  .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
@@ -41,6 +74,7 @@ green:
   ;; @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
@@ -54,13 +88,21 @@ _start:
   ;; initialize stack pointer with value from linker
   mov.w   #__stack, SP
 
-  mov.w   #0xaaaa, r7
-  mov.w   #0x5555, r8
-
 init:
   ;; configuration of GPIO Ports
-  mov.b   #BIT0|BIT1|BIT2,&P1DIR
+  ;; BIT0: data bit
+  ;; BIT1: output enable
+  ;; BIT2: debug
+  ;; BIT3: Signal waiting for data
+  mov.b   #BIT0|BIT1|BIT2|BIT3, &P1DIR
   mov.b   #0,&P1OUT
+  ;; BIT5: spi, UCB0CLK
+  ;; BIT6: spi, UCB0SOMI
+  ;; BIT7: spi, UCB0SIMO
+  mov.b   #BIT5|BIT6|BIT7, &P1SEL
+  mov.b   #BIT5|BIT6|BIT7, &P1SEL2
+  ;; BIT4: long pulse
+  ;; BIT1: short pulse
   mov.b   #BIT1|BIT4,&P2DIR
   mov.b   #BIT1|BIT4,&P2SEL
 
@@ -69,24 +111,22 @@ init:
   ;;  cycle time is 56.25ns
   mov.w   #ID_0|MC_0|TACLR|TASSEL_2,&TA1CTL
   ;;  2.0us 
-  mov.w   #45,&TA1CCR0
+  mov.w   #TIMER_COMPLETE,&TA1CCR0
   ;;  a bit less
-  mov.w   #10,&TA1CCR1
+  mov.w   #TIMER_SHORT,&TA1CCR1
-  mov.w   #22,&TA1CCR2
+  mov.w   #TIMER_LONG,&TA1CCR2
   ;;  configure output mode for TA0.1
   mov.w   #CCIE,&TA1CCTL0
   mov.w   #OUTMOD_7,&TA1CCTL1
   mov.w   #OUTMOD_7,&TA1CCTL2
 
-  ;; initialize bit-counter for isr
+  ;; spi configuration
-  mov.b   #0x01,r6
+  ;;  USCI B to slave mode
-  ;; initialize isr-sync register, signal BYTE_DONE for the first start
+  mov.b   #UCSYNC, &UCB0CTL0
-  mov.b   #0x01,r4
+  mov.b   #0x00, &UCB0CTL1
 
-  ;; screen data start/next into r7
+  ;; make sure the isr will not immediately start
-  mov.w   #screendata, r7
+  mov.b   #SIGNAL_INIT_VALUE, SIGNAL_REGISTER
-  ;; screen data end into r8
-  mov.w   #screendataend, r8
 
   ;; start timer in up mode
   bis.w   #MC0,&TA1CTL
@@ -94,90 +134,251 @@ init:
   eint
 
 
-
+;; ----------------------------------------------------
-
-  ;; r4: synchronization between mainloop and isr
-  ;; r5: data byte to be handled by isr
 mainloop:
+  call    #forwardscreen_init
+  call    #resetscreen
+
+mainloop_draw:
+  call    #drawscreen
+
+  ;; signal waiting for data
+  set_signal_waiting_for_data
+
+  ;call    #forwardscreen
+  ;call    #wait
+  call    #receivedata
+
+  ;; data has been received, clear signal
+  clear_signal_waiting_for_data
+
+  jmp     mainloop_draw
+
+
+;; ----------------------------------------------------
+wait:
+  push    r11
+  push    r12
+
+  mov.w   #0x0040, r11
+wait_continue_1:
+  mov.w   #0xffff, r12
+wait_continue_2:
+  dec.w   r12
+  jnz     wait_continue_2
+  dec.w   r11
+  jnz     wait_continue_1
+
+  pop     r12
+  pop     r11
+  ret
+
+
+;; ----------------------------------------------------
+forwardscreen_init:
+  mov.w   #screendata, &data_forward_pointer
+  ret
+
+;; ----------------------------------------------------
+forwardscreen:
+  push    r8
+  push    r10
+
+  mov.w   #screendataend, r8
+  mov.w   data_forward_pointer, r10
+  mov.b   #_off, @r10
+  inc.w   r10
+  mov.b   #_blue, @r10
+  cmp.w   r10, r8
+  jnz     forwardscreen_done
+  mov.w   #screendata, r10
+forwardscreen_done:
+  mov.w   r10, data_forward_pointer
+
+  pop     r10
+  pop     r8
+  ret
+  
+
+;; ----------------------------------------------------
+resetscreen:
+  push    r7
+  push    r8
+
+  ;; reset screen data
+  mov.w   #screendata, r7
+  mov.w   #screendataend, r8
+resetscreen_continue:
+  mov.b   #_off, @r7
+  inc.w   r7
+  cmp.w   r7, r8
+  jnz resetscreen_continue
+
+  pop     r8
+  pop     r7
+  ret
+
+
+;; ----------------------------------------------------
+receivedata:
+  push    r9
+  push    r10
+
+  ;; wait for first octet
+receivedata_wait_for_control_octet:
+  bit     #UCB0RXIFG, &UC0IFG
+  jz      receivedata_wait_for_control_octet
+
+  ;; get control or address octet from buffer register
+  mov.b   UCB0RXBUF, r9
+  ;; check whether value == 0xff (wait for the whole
+  ;; set of data to fill the screendata)
+  cmp.b   #0xff, r9
+  ;; 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
+
+  ;; it is an address octet
+receivedata_wait_for_octet:
+  bit     #UCB0RXIFG, &UC0IFG
+  jz      receivedata_wait_for_octet
+
+  ;; get data octet from buffer register
+  mov.b   UCB0RXBUF, r10
+  ;; move it to the destination
+  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
+  ret
+
+
+;; ----------------------------------------------------
+drawscreen:
+  push    r7
+  push    r8
+  push    r9
+
+#define DATA_NEXT_ADDRESS_REGISTER r7
+#define DATA_END_ADDRESS_REGISTER r8
+#define NEXT_DATA_REGISTER r9
+
+  ;; initialize bit-counter for isr
+  mov.b   #BIT_COUNTER_INIT_VALUE, BIT_COUNTER_REGISTER
+  ;; initialize isr-sync register, signal BYTE_DONE for the first start
+  mov.b   #SIGNAL_OCTET_DONE, SIGNAL_REGISTER
+
+  ;; screen data start/next into r7
+  mov.w   #screendata, DATA_NEXT_ADDRESS_REGISTER
+  ;; screen data end into r8
+  mov.w   #screendataend, DATA_END_ADDRESS_REGISTER
+
+drawscreen_continue:
   ;; prepare next byte to handle by isr
-  cmp.w   r7,r8
+  cmp.w   DATA_NEXT_ADDRESS_REGISTER, DATA_END_ADDRESS_REGISTER
-  jz      mainloop_data_done
+  jz      drawscreen_data_done
 
   ;; load next data byte
-  mov.b   @r7,r9
+  mov.b   @DATA_NEXT_ADDRESS_REGISTER, NEXT_DATA_REGISTER
-  inc.w   r7
+  inc.w   DATA_NEXT_ADDRESS_REGISTER
 
-mainloop_wait_for_isr:
+  ;; multiple color code by four to get color data
-  ;; check bit0 in sync register
+  rla.b   NEXT_DATA_REGISTER
-  bit     #0x01,r4
+  rla.b   NEXT_DATA_REGISTER
-  jz      mainloop_wait_for_isr
 
-  ;; load data
-  mov.b   r9,r5
-  ;; clear BYTE_DONE
-  bic     #0x01, r4
   ;; enable isr
-  bis     #0x02, r4
+  bis     #SIGNAL_ISR_ENABLE, SIGNAL_REGISTER
+
+drawscreen_wait_for_isr_0:
+  ;; check bit0 in sync register
+  bit     #SIGNAL_OCTET_DONE, SIGNAL_REGISTER
+  jz      drawscreen_wait_for_isr_0
+  ;; load data
+  mov.b   colors(NEXT_DATA_REGISTER), DATA_REGISTER
+  ;; clear BYTE_DONE
+  bic     #SIGNAL_OCTET_DONE,  SIGNAL_REGISTER
+drawscreen_wait_for_isr_1:
+  ;; check bit0 in sync register
+  bit     #SIGNAL_OCTET_DONE, SIGNAL_REGISTER
+  jz      drawscreen_wait_for_isr_1
+  ;; load data
+  mov.b   colors+1(NEXT_DATA_REGISTER), DATA_REGISTER
+  ;; clear BYTE_DONE
+  bic     #SIGNAL_OCTET_DONE,  SIGNAL_REGISTER
+drawscreen_wait_for_isr_2:
+  ;; check bit0 in sync register
+  bit     #SIGNAL_OCTET_DONE, SIGNAL_REGISTER
+  jz      drawscreen_wait_for_isr_2
+  ;; load data
+  mov.b   colors+2(NEXT_DATA_REGISTER), DATA_REGISTER
+  ;; clear BYTE_DONE
+  bic     #SIGNAL_OCTET_DONE,  SIGNAL_REGISTER
 
   ;; continue
-  jmp     mainloop
+  jmp     drawscreen_continue
 
-mainloop_data_done:
+drawscreen_data_done:
   ;; signal all data processed, isr finish
-  bis     #0x04, r4
+  bis     #SIGNAL_ALL_DATA_DONE,  SIGNAL_REGISTER
-  bis     #BIT2, &P1OUT
+
-  ;; continue
+  pop     r9
-  jmp     mainloop
+  pop     r8
-
+  pop     r7
-
+  ret
 
 
+;; ----------------------------------------------------
 ; --- timer isr ---
   ;; r6: exclusively used by isr as bit-counter
 timer1_a0_isr:
   ;; check isr enable bit
-  bit     #0x02,r4
+  bit     #SIGNAL_ISR_ENABLE, SIGNAL_REGISTER
   jz      timer1_a0_isr_exit
 
   ;; shift msb of data register r5 into carry flag and set or reset P1.0 accordingly
-  rla.b   r5
+  rla.b   DATA_REGISTER
   jnc     timer1_a0_isr_false_bit
-  bis     #BIT0,&P1OUT
+  set_data_bit
   jmp     timer1_a0_isr_end
 timer1_a0_isr_false_bit:
-  bic     #BIT0,&P1OUT
+  clear_data_bit
    
 timer1_a0_isr_end:
   ;; enable output
-  bis     #BIT1, &P1OUT
+  set_output_enable
 
   ;; roll bit-counter
-  rla.b   r6
+  rla.b   BIT_COUNTER_REGISTER
   jnc     timer1_a0_isr_exit
 
   ;; reset bit-counter
-  mov.b   #0x01,r6
+  mov.b   #BIT_COUNTER_INIT_VALUE, BIT_COUNTER_REGISTER
   ;; signal byte done
-  bis     #0x01,r4
+  bis     #SIGNAL_OCTET_DONE, SIGNAL_REGISTER
 
-  bit     #0x04, r4
+  ;; check whether all data are processed
+  bit     #SIGNAL_ALL_DATA_DONE,  SIGNAL_REGISTER
   jz      timer1_a0_isr_exit
   ;; disable isr
-  bic     #0x02, r4
+  bic     #SIGNAL_ISR_ENABLE,  SIGNAL_REGISTER
   ;; disable output
-  bic     #BIT1, &P1OUT
+  clear_output_enable
 
 timer1_a0_isr_exit:
   reti
 
 
-
+;; ----------------------------------------------------
-;timer0_a1_isr:
-;  reti
-
-; --- interrupt vectors ---
-;  .section "__interrupt_vector_9","ax",@progbits
-;  .word   timer0_a1_isr
   .section "__interrupt_vector_14","ax",@progbits
   .word   timer1_a0_isr
 
@@ -186,3 +387,6 @@ timer1_a0_isr_exit:
   .word   _start
 
   .end
+
+
+

readme.md

@@ -1,5 +1,97 @@
+## Debugging
+
+```
 mspdebug rf2500 gdb
+
 msp430-gdb -x firmware.gdb
+```
 
 Attention: the gdb in the TI toolchain package is broken, use the one from Debian
 
+
+
+## Signals Working Cycler
+
+These signals are related to code under tag `cycler_works_include_output_stage`.
+
+First octets:
+
+![](./docs/cycler_working_first_octets.png)
+
+Last octets:
+
+![](./docs/cycler_working_last_octets.png)
+
+Schematics and legend for signals:
+
+![](./docs/schematics.jpeg)
+
+
+## Timing
+
+Complete cycle: 2.48us
+
+![](./docs/pulse_complete.png)
+
+Short pulse: 550ns
+
+![](./docs/pulse_short.png)
+
+Long pulse: 1.18us
+
+![](./docs/pulse_long.png)
+
+
+## Load Time
+
+During of loading data into five LEDs: 297us
+
+![](./docs/five_leds.png)
+
+During of loading data into six LEDs: 297us
+
+![](./docs/six_leds.png)
+
+
+| # of LEDs | Load Time measured | calculated |
+| --------- | ------------------ | ---------- |
+| 5         | 297us              |            | 
+| 6         | 354us              | 356.4us    |
+| 10        |                    | 594us      |
+| 100       |                    | 5.9ms      |
+| 200       |                    | 11.8ms     |
+
+
+## Reset Circuitry
+
+It appears that the output voltage of the power supply raises that slow, that the MCU
+will not handle the reset correctly.
+
+The following circuitry should generate a valid reset signal far enough from the raise 
+of the supply voltage:
+
+![](./docs/reset-circuit.jpeg)
+
+The circuit generates the following signals:
+
+![](./docs/reset-signal.png)
+
+#### Reference voltage (green):
+
+```math
+U_ref = 3.3V \frac{22k\Omega}{22k\Omega + 10k\Omega} = 2.2V
+```  
+  
+
+#### Trigger voltage (purple):
+
+```math
+U_trigg = 3.3V \frac{330k\Omega}{330k\Omega + 82k\Omega} = 2.64V
+```  
+  
+
+#### RC constant:
+
+```math
+\tau = 82k\Omega \cdot 100nF = 8.2ms
+```