changes for spi

colors.S

@@ -1,71 +1,7 @@
 #include "colors.h"
 
+#define DIMM_FACTOR 3
   .section ".rodata","a"
-screendata_tmpl:
-  .global screendata_tmpl
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-  .byte _green
-screendataend_tmpl:
-  .byte   0xff
-
 ;; color definitions according to
 ;; https://learn.sparkfun.com/tutorials/lilypad-protosnap-plus-activity-guide/3-custom-color-mixing
 colors:
@@ -74,29 +10,29 @@ colors:
 off:
   .byte   0x00, 0x00, 0x00, 0
 blue:
-  .byte   0x00, 0x00, 0xff, 0
+  .byte   0x00>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
 green:
-  .byte   0x00, 0xff, 0x00, 0
+  .byte   0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
 orange:
-  .byte   0xff, 0x80, 0x00, 0
+  .byte   0xff>>DIMM_FACTOR, 0x80>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
 rose:
-  .byte   0xff, 0x00, 0x80, 0
+  .byte   0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0x80>>DIMM_FACTOR, 0
 magenta:
-  .byte   0xff, 0x00, 0xff, 0
+  .byte   0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
 violet:
-  .byte   0x80, 0x00, 0xff, 0
+  .byte   0x80>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
 azure:
-  .byte   0x00, 0x80, 0xff, 0
+  .byte   0x00>>DIMM_FACTOR, 0x80>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
 cyan:
-  .byte   0x00, 0xff, 0xff, 0
+  .byte   0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
 springgreen:
-  .byte   0x00, 0xff, 0x80, 0
+  .byte   0x00>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0x80>>DIMM_FACTOR, 0
 chartreuse:
-  .byte   0x80, 0xff, 0x00, 0
+  .byte   0x80>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
 yellow:
-  .byte   0xff, 0xff, 0x00, 0
+  .byte   0xff>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
 white:
-  .byte   0xff, 0xff, 0xff, 0
+  .byte   0xff>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0xff>>DIMM_FACTOR, 0
 red:
-  .byte   0xff, 0x00, 0x00, 0
+  .byte   0xff>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0x00>>DIMM_FACTOR, 0
 

main.S

@@ -6,20 +6,23 @@
 #define SR r2
 
 
+;; ----------------------------------------------------
+;; --- r4, r5 and r6 must not be used for any other ---
+;; --- purpose                                      ---
+;; required for communication between drawscreen and shifter 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 DATA_NEXT_ADDRESS_REGISTER r7
-#define DATA_END_ADDRESS_REGISTER r8
+;; required for handover of data between drawscreen and isr
 #define DATA_REGISTER r5
-#define NEXT_DATA_REGISTER r9
 
+;; required for sequencing of isr
 #define BIT_COUNTER_REGISTER r6
 #define BIT_COUNTER_INIT_VALUE 0x01
-
+;; ----------------------------------------------------
 
 
 ;; 2.48us
@@ -47,14 +50,22 @@
   .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:
-  .rept 60
+  .rept 60 ;; number of leds in hardward
   .byte 0
   .endr
 screendataend:
   .byte 0xff
+data_forward_pointer:
+  .word 0
 
 
   ;; .text is the name of the section, it is a hint for the linker to
@@ -63,6 +74,7 @@ screendataend:
   ;; @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
@@ -76,30 +88,21 @@ _start:
   ;; initialize stack pointer with value from linker
   mov.w   #__stack, SP
 
-  ;; ----------------------------------------------
-  ;; load data from template area in rom into ram
-  ;; uses arbitrary register before loading registers
-  ;; for later use
-  mov.w   #screendata, r7
-  mov.w   #screendataend, r8
-  mov.w   #screendata_tmpl, r9
-_start_load_next:
-  mov.b   @r9, @r7
-  inc.w   r7
-  inc.w   r9
-  cmp.w   r7, r8
-  jnz _start_load_next
-  ;; ----------------------------------------------
-
 init:
   ;; configuration of GPIO Ports
   ;; BIT0: data bit
   ;; BIT1: output enable
   ;; BIT2: debug
-  mov.b   #BIT0|BIT1|BIT2,&P1DIR
+  ;; BIT3: Signal waiting for data
+  mov.b   #BIT0|BIT1|BIT2|BIT3, &P1DIR
   mov.b   #0,&P1OUT
-  ;; BIT4: long pulse
-  ;; BIT1: short pulse
+  ;; BIT5: spi, UCB0CLK
+  ;; BIT6: spi, UCB0SOMI
+  ;; 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
 
@@ -117,6 +120,179 @@ init:
   mov.w   #OUTMOD_7,&TA1CCTL1
   mov.w   #OUTMOD_7,&TA1CCTL2
 
+  ;; spi configuration
+  ;;  USCI B to slave mode
+  mov.b   #0x00, &UCB0CTL0
+  mov.b   #0x00, &UCB0CTL1
+
+  ;; make sure the isr will not immediately start
+  mov.b   #SIGNAL_INIT_VALUE, SIGNAL_REGISTER
+
+  ;; start timer in up mode
+  bis.w   #MC0,&TA1CTL
+  ;; enable interrupts
+  eint
+
+
+;; ----------------------------------------------------
+mainloop:
+  ;call    #forwardscreen_init
+  call    #resetscreen
+
+mainloop_draw:
+  call    #drawscreen
+
+  ;; signal waiting for data
+  set_signal_waiting_for_data
+
+  call    #forwardscreen
+  call    #wait
+
+  ;; receive data via spi
+  ;call    #receivedata
+
+  ;; data has been received, clear signal
+  clear_signal_waiting_for_data
+
+
+  jmp     mainloop_draw
+
+
+;; ----------------------------------------------------
+wait:
+  push    r11
+  push    r12
+
+  mov.w   #0x0010, 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   #_white, @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    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:
+  bit     #UCB0RXIFG, &UC0IFG
+  jz      receivedata_wait_for_first_octet
+
+  ;; get data 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
+
+  ;; if it is not 0xff, it is the octet number which is the
+  ;; relative address within screendata
+receivedata_wait_for_octet:
+  bit     #UCB0RXIFG, &UC0IFG
+  jz      receivedata_wait_for_octet
+
+  ;; get octet from buffer register
+  mov.b   UCB0RXBUF, r10
+
+  ;; move it to the destination
+  mov.b   r10, screendata(r9) 
+  
+  ;; done
+  jmp     receivedata_end
+
+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
+  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
@@ -127,15 +303,10 @@ init:
   ;; screen data end into r8
   mov.w   #screendataend, DATA_END_ADDRESS_REGISTER
 
-  ;; start timer in up mode
-  bis.w   #MC0,&TA1CTL
-  ;; enable interrupts
-  eint
-
-mainloop:
+drawscreen_continue:
   ;; prepare next byte to handle by isr
   cmp.w   DATA_NEXT_ADDRESS_REGISTER, DATA_END_ADDRESS_REGISTER
-  jz      mainloop_data_done
+  jz      drawscreen_data_done
 
   ;; load next data byte
   mov.b   @DATA_NEXT_ADDRESS_REGISTER, NEXT_DATA_REGISTER
@@ -148,68 +319,67 @@ mainloop:
   ;; enable isr
   bis     #SIGNAL_ISR_ENABLE, SIGNAL_REGISTER
 
-mainloop_wait_for_isr_0:
+drawscreen_wait_for_isr_0:
   ;; check bit0 in sync register
   bit     #SIGNAL_OCTET_DONE, SIGNAL_REGISTER
-  jz      mainloop_wait_for_isr_0
+  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
-mainloop_wait_for_isr_1:
+drawscreen_wait_for_isr_1:
   ;; check bit0 in sync register
   bit     #SIGNAL_OCTET_DONE, SIGNAL_REGISTER
-  jz      mainloop_wait_for_isr_1
+  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
-mainloop_wait_for_isr_2:
+drawscreen_wait_for_isr_2:
   ;; check bit0 in sync register
   bit     #SIGNAL_OCTET_DONE, SIGNAL_REGISTER
-  jz      mainloop_wait_for_isr_2
+  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     #SIGNAL_ALL_DATA_DONE,  SIGNAL_REGISTER
 
-
-  jmp     mainloop_data_done
-
-
-
-
+  pop     r9
+  pop     r8
+  pop     r7
+  ret
 
 
+;; ----------------------------------------------------
 ; --- timer isr ---
   ;; r6: exclusively used by isr as bit-counter
-timer1_a0_isr:
+shifter_isr:
   ;; check isr enable bit
   bit     #SIGNAL_ISR_ENABLE, SIGNAL_REGISTER
-  jz      timer1_a0_isr_exit
+  jz      shifter_isr_exit
 
   ;; shift msb of data register r5 into carry flag and set or reset P1.0 accordingly
   rla.b   DATA_REGISTER
-  jnc     timer1_a0_isr_false_bit
+  jnc     shifter_isr_false_bit
   set_data_bit
-  jmp     timer1_a0_isr_end
-timer1_a0_isr_false_bit:
+  jmp     shifter_isr_end
+shifter_isr_false_bit:
   clear_data_bit
    
-timer1_a0_isr_end:
+shifter_isr_end:
   ;; enable output
   set_output_enable
 
   ;; roll bit-counter
   rla.b   BIT_COUNTER_REGISTER
-  jnc     timer1_a0_isr_exit
+  jnc     shifter_isr_exit
 
   ;; reset bit-counter
   mov.b   #BIT_COUNTER_INIT_VALUE, BIT_COUNTER_REGISTER
@@ -218,19 +388,19 @@ timer1_a0_isr_end:
 
   ;; check whether all data are processed
   bit     #SIGNAL_ALL_DATA_DONE,  SIGNAL_REGISTER
-  jz      timer1_a0_isr_exit
+  jz      shifter_isr_exit
   ;; disable isr
   bic     #SIGNAL_ISR_ENABLE,  SIGNAL_REGISTER
   ;; disable output
   clear_output_enable
 
-timer1_a0_isr_exit:
+shifter_isr_exit:
   reti
 
 
-
+;; ----------------------------------------------------
   .section "__interrupt_vector_14","ax",@progbits
-  .word   timer1_a0_isr
+  .word   shifter_isr
 
   ;; .resetvec comes from linker
   .section ".resetvec","ax",@progbits

readme.md

@@ -61,3 +61,37 @@ During of loading data into six LEDs: 297us
 | 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
+```