wn/rgb-driver-01
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use names instead of registers

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This commit is contained in:
Wolfgang Hottgenroth
2024-02-25 19:56:57 +01:00
parent a5ffaa05bd
commit 9fed0c4657
1 changed files with 66 additions and 60 deletions
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82
main.S
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@ -7,6 +7,29 @@
#define SP r1 #define SP r1
#define SR r2 #define SR r2
;; --- register usage --------------------------------
;; r4: synchronization between main loop and isr
;; bit0 signals byte done from isr
;; r5: data byte to be handled by isr
;; r6: bit-counter, only used within isr
;; r7: screen data start/next pointer
;; r8: screen data end pointer
;; r9: next screen data byte, prepared in mainloop
#define SIGNAL_INIT_VALUE 0x00
#define SIGNAL_BYTE_DONE 0x01
#define SIGNAL_ISR_ENABLE 0x02
#define SIGNAL_REGISTER r4
#define DATA_BYTE_REGISTER r5
#define NEXT_DATA_BYTE_REGISTER r9
#define DATA_NEXT_ADDRESS_REGISTER r7
#define DATA_LAST_ADDRESS_REGISTER r8
#define BIT_COUNTER_REGISTER r6
#define BIT_COUNTER_INIT_VALUE 0x01
;; ---------------------------------------------------
.section ".rodata","a" .section ".rodata","a"
screendata: screendata:
@ -74,26 +97,18 @@ init:
mov.w #OUTMOD_7, &TA1CCTL1 mov.w #OUTMOD_7, &TA1CCTL1
mov.w #OUTMOD_7, &TA1CCTL2 mov.w #OUTMOD_7, &TA1CCTL2
;; r4: synchronization between main loop and isr
;; bit0 signals byte done from isr
;; r5: data byte to be handled by isr
;; r6: bit-counter, only used within isr
;; r7: screen data start/next pointer
;; r8: screen data end pointer
;; r9: next screen data byte, prepared in mainloop
;; initialize bit-counter for isr ;; initialize bit-counter for isr
mov.b #0x01,r6 mov.b #BIT_COUNTER_INIT_VALUE, BIT_COUNTER_REGISTER
;; initialize isr-sync register ;; initialize isr-sync register
mov.b #0x00,r4 mov.b #SIGNAL_INIT_VALUE, SIGNAL_REGISTER
;; screen data start/next into r7 ;; screen data start/next into DATA_NEXT_ADDRESS_REGISTER
mov.w #screendata, r7 mov.w #screendata, DATA_NEXT_ADDRESS_REGISTER
;; screen data end into r8 ;; screen data end into DATA_LAST_ADDRESS_REGISTER
mov.w #screendataend, r8 mov.w #screendataend, DATA_LAST_ADDRESS_REGISTER
;; load first screen data value into r5 ;; load first screen data value into DATA_BYTE_REGISTER
mov.b @r7,r5 mov.b @DATA_NEXT_ADDRESS_REGISTER, DATA_BYTE_REGISTER
inc.w r7 inc.w DATA_NEXT_ADDRESS_REGISTER
;; start timer in up mode ;; start timer in up mode
bis.w #MC0, &TA1CTL bis.w #MC0, &TA1CTL
@ -104,26 +119,26 @@ init:
mainloop: mainloop:
;; prepare next byte to handle by isr ;; prepare next byte to handle by isr
;; first, check whether we are already at the end of screen data ;; first, check whether we are already at the end of screen data
cmp.w r7,r8 cmp.w DATA_NEXT_ADDRESS_REGISTER, DATA_LAST_ADDRESS_REGISTER
jnz mainloop_prepare_next_byte jnz mainloop_prepare_next_byte
;; in that case rollover to the start again ;; in that case rollover to the start again
mov.w #screendata,r7 mov.w #screendata, DATA_NEXT_ADDRESS_REGISTER
mainloop_prepare_next_byte: mainloop_prepare_next_byte:
;; load the byte from the screen data next pointer ;; load the byte from the screen data next pointer
mov.b @r7,r9 mov.b @DATA_NEXT_ADDRESS_REGISTER, NEXT_DATA_BYTE_REGISTER
;; and increase the pointer ;; and increase the pointer
inc.w r7 inc.w DATA_NEXT_ADDRESS_REGISTER
mainloop_wait_for_isr: mainloop_wait_for_isr:
;; check bit0 in sync register, wait for the signal from ;; check bit0 in sync register, wait for the signal from
;; the isr ;; the isr
bit #0x01,r4 bit #SIGNAL_BYTE_DONE, SIGNAL_REGISTER
jz mainloop_wait_for_isr jz mainloop_wait_for_isr
;; load data ;; load data
mov.b r9,r5 mov.b NEXT_DATA_BYTE_REGISTER, DATA_BYTE_REGISTER
;; clear the signal ;; clear the signal
mov.b #0x00,r4 bic #SIGNAL_BYTE_DONE, SIGNAL_REGISTER
;; mark the cycle ;; mark the cycle
bis #BIT2, &P1OUT bis #BIT2, &P1OUT
bic #BIT2, &P1OUT bic #BIT2, &P1OUT
@ -138,11 +153,11 @@ timer1_a0_isr:
;; func begin marker ;; func begin marker
bis #BIT0, &P1OUT bis #BIT0, &P1OUT
;; check isr idle bit ;; check isr idle bit
bit #BIT1,r4 bit #SIGNAL_ISR_ENABLE, SIGNAL_REGISTER
jnz timer1_a0_isr_exit jnz timer1_a0_isr_exit
;; shift msb of data register r5 into carry flag and set or reset P1.1 accordingly ;; shift msb of data register r5 into carry flag and set or reset P1.1 accordingly
rla.b r5 rla.b DATA_BYTE_REGISTER
jnc timer1_a0_isr_false_bit jnc timer1_a0_isr_false_bit
bis #BIT1, &P1OUT bis #BIT1, &P1OUT
jmp timer1_a0_isr_end jmp timer1_a0_isr_end
@ -151,13 +166,13 @@ timer1_a0_isr_false_bit:
;; shift bit-counter, after eight shifts signal byte done and reset bit-counter ;; shift bit-counter, after eight shifts signal byte done and reset bit-counter
timer1_a0_isr_end: timer1_a0_isr_end:
rla.b r6 rla.b BIT_COUNTER_REGISTER
jnc timer1_a0_isr_exit jnc timer1_a0_isr_exit
;; reset bit-counter ;; reset bit-counter
mov.b #0x01,r6 mov.b #BIT_COUNTER_INIT_VALUE, BIT_COUNTER_REGISTER
;; signal byte done ;; signal byte done
mov.b #0x01,r4 bis #SIGNAL_BYTE_DONE, SIGNAL_REGISTER
timer1_a0_isr_exit: timer1_a0_isr_exit:
;; func end marker ;; func end marker
@ -166,15 +181,6 @@ timer1_a0_isr_exit:
;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
;; .resetvec comes from linker ;; .resetvec comes from linker
.section ".resetvec","ax",@progbits .section ".resetvec","ax",@progbits
.word _start .word _start