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avr: fixed code for DS18B20 (works now!).

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This commit is contained in:
Martin Preuss
2024-09-12 11:42:59 +02:00
parent 39933a957b
commit 0fabc6d613
1 changed files with 49 additions and 15 deletions
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64
avr/modules/ds18b20/main.asm
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@@ -20,6 +20,7 @@
.equ DS18B20_FLAGS_CONV_STARTED = 0x01 .equ DS18B20_FLAGS_CONV_STARTED = 0x01
.equ DS18B20_FLAGS_CONV_UPDATED = 0x02 .equ DS18B20_FLAGS_CONV_UPDATED = 0x02
.equ DS18B20_POLYNOMIAL = 0x8c
; *************************************************************************** ; ***************************************************************************
@@ -96,13 +97,13 @@ Ds18b20_OnTimer:
; conversion complete, read value, set flags ; conversion complete, read value, set flags
ldi xl, LOW(ds18b20DataBuffer) ldi xl, LOW(ds18b20DataBuffer)
ldi xh, HIGH(ds18b20DataBuffer) ldi xh, HIGH(ds18b20DataBuffer)
in r15, SREG
push r15 push r15
in r15, SREG
cli cli
rcall ds18b20ReadScratchPad rcall ds18b20ReadScratchPad
brcc Ds18b20_OnTimer_popr15ret brcc Ds18b20_OnTimer_popr15ret
out SREG, r15
pop r15 pop r15
out SREG, r15
ld r16, X+ ; copy temp from scratchpad ld r16, X+ ; copy temp from scratchpad
sts ds18b20DataTemp, r16 sts ds18b20DataTemp, r16
@@ -116,8 +117,8 @@ Ds18b20_OnTimer:
ret ret
Ds18b20_OnTimer_startConversion: Ds18b20_OnTimer_startConversion:
in r15, SREG
push r15 push r15
in r15, SREG
cli cli
ldi r16, DS18B20_FNCMD_CONVERT ldi r16, DS18B20_FNCMD_CONVERT
rcall Ds18b20_SendCommand rcall Ds18b20_SendCommand
@@ -126,8 +127,8 @@ Ds18b20_OnTimer_startConversion:
ori r16, DS18B20_FLAGS_CONV_STARTED ori r16, DS18B20_FLAGS_CONV_STARTED
sts ds18b20Flags, r16 sts ds18b20Flags, r16
Ds18b20_OnTimer_popr15ret: Ds18b20_OnTimer_popr15ret:
out SREG, r15
pop r15 pop r15
out SREG, r15
Ds18b20_OnTimer_done: Ds18b20_OnTimer_done:
ret ret
@@ -190,11 +191,10 @@ Ds18b20_ReadRom_loop1:
dec r23 dec r23
brne Ds18b20_ReadRom_loop1 brne Ds18b20_ReadRom_loop1
sbiw xh:xl, 8 sbiw xh:xl, 8
ldi r18, 7 ldi r18, 8
ldi r19, 0x99 ldi r19, DS18B20_POLYNOMIAL
rcall crc8Calc ; (R16, R17, R18, R20, X) rcall ds18b20Crc8Calc ; (R16, R17, R18, R20, R21, X)
ld r17, X+ tst r16
cp r16, r17
brne Ds18b20_ReadRom_error brne Ds18b20_ReadRom_error
sec sec
ret ret
@@ -229,12 +229,11 @@ ds18b20ReadScratchPad_loop1:
dec r23 dec r23
brne ds18b20ReadScratchPad_loop1 brne ds18b20ReadScratchPad_loop1
sbiw xh:xl, 9 sbiw xh:xl, 9
ldi r18, 8 ldi r18, 9
ldi r19, 0x99 ldi r19, DS18B20_POLYNOMIAL
rcall crc8Calc ; (R16, R17, R18, R20, X) rcall ds18b20Crc8Calc ; (R16, R17, R18, R20, R21, X)
ld r17, X+ tst r16
cp r16, r17 brne ds18b20ReadScratchPad_error
; brne ds18b20ReadScratchPad_error
sbiw xh:xl, 9 sbiw xh:xl, 9
sec sec
ret ret
@@ -260,6 +259,41 @@ Ds18b20_SendTemp:
; ---------------------------------------------------------------------------
; @routine ds18b20Crc8Calc @global
; calc crc8 checksum using given polynomial
;
; @return r16 crc8 checksum
; @return X points directly after last checked byte
; @param X pointer to data to calc crc8 for
; @param r18 number of bytes to calc crc8 for
; @param r19 polynomial to use
; @clobbers: R16, R17, R18, R20, R21, X
ds18b20Crc8Calc:
clr r16 ; start crc
ds18b20Crc8Calc_loop1:
ld r17, X+ ; running var
ldi r20, 8 ; counter for loop2
ds18b20Crc8Calc_loop2: ; r16=crc so far, r17=current inbyte
mov r21, r16
lsr r16
eor r21, r17
lsr r17
andi r21, 1
breq ds18b20Crc8Calc_withoutPoly
eor r16, r19
ds18b20Crc8Calc_withoutPoly:
dec r20
brne ds18b20Crc8Calc_loop2
dec r18
brne ds18b20Crc8Calc_loop1
ret
; @end
DS18B20_END: DS18B20_END:
.equ MODULE_SIZE_DS18B20 = DS18B20_END-DS18B20_BEGIN .equ MODULE_SIZE_DS18B20 = DS18B20_END-DS18B20_BEGIN