DS1820 Thermometer
DS1820 Thermometer circuit schematic
Download project from here.
This DS18S20 digital thermometer provides a precision of 0.5 °C and SCRATCHPAD it's read at every 800ms. Capacitors C5,C6 and diodes D8,D8 makes a voltage doublers witch power the lcd panel.
;=====lcd digital thermometer with ds18s20 Version 2.1======14/11/03==
; iic lcd driver: PCF2103
; ra0,ra1 iic sclock, sdata
; ra2,ra3 pwm, ds1820 data I/O
; internal clock
; standard crystal 4.194 MHz XT - .95us pe instructiune
; www.module.ro
;------------------------------------------------------------
list p=16f84;f=inhx8m
#INCLUDE P16F84.INC
_CP_OFF equ H'3FFF' ;code protect off
_PwRTE_ON equ H'3FFF' ;Power on timer on
_wDT_OFF equ H'3FFB' ;watch dog timer off
_XT_OSC equ H'3FFD' ;crystal oscillator
__CONFIG _CP_OFF & _PwRTE_ON & _wDT_OFF & _XT_OSC
;------------------------------------------------------------
; cpu init
count1 equ 0C
count2 equ 0D
count3 equ 0E
transo equ 0F
ratb equ 10
dig1 equ 11
dig2 equ 12
dig3 equ 13
semn equ 14
#DEFINE sclk PORTA,0
#DEFINE sdta PORTA,1
#DEFINE osc PORTA,2
#DEFINE grad PORTA,3
;------------------------------------------------------------
;------------------------------------------------------------
; cpu init
org 0x00
goto init
org 0x04
;
;------------------------------------------------------------
init call usaex
call usbex
movlw 0x00
movwf PORTA
movwf PORTB
clrf semn
;***************************************************
;***************************************************
;* Lcd init commands *
;***************************************************
lcd_ini
call iict ; i2c start
movlw 0x74 ; device write address (75h for read)
call act ; i2c send subroutine
movlw 0x00 ; Co,RS=0, set instruction register for multiple next command bytes
call act
movlw 0x31 ; extended instruction set
call act
movlw 0x02 ; set screen configuration left to right
call act
movlw 0x05 ; set display configuration
call act
movlw 0x08 ; set icon mode, full mode, icon blink disable
call act
movlw 0x30 ; normal instruction set
call act
movlw 0x0C ; set display on
call act
movlw 0x06 ; set cursor move direction
call act
movlw 0x02 ; set DDRAM address 0 in address counter
call act
call iicp ; i2c stop
;***************************************************
;* Lcd icon sets off *
;***************************************************
call iict
movlw 0x74
call act
movlw 0x80 ; Co=1, RS=0 just one next command byte
call act
movlw 0x4C ; set CGRAM for icons
call act
movlw 0x40 ; Co=0, RS=1, set instruction register for multiple next data bytes
call act
movlw 0x00 ; erase icons sequence
call act
movlw 0x18
call act
movlw 0x00
call act
movlw 0x00
call act
movlw 0x00
call act
movlw 0x00
call act
movlw 0x00
call act
movlw 0x00
call act
movlw 0x00
call act
movlw 0x00
call act
movlw 0x00
call act
movlw 0x00
call act
movlw 0x0F
call act
movlw 0x10
call act
call iicp ; i2c stop
;***************************************************
;* Lcd cursor subroutine *
;***************************************************
call iict
movlw 0x74
call act
movlw 0x00
call act
movlw 0x30
call act
movlw 0x01 ; clears entire display and sets DDRAM address to 0 in address counter
call act
movlw 0x0C ; display on, cursor off, cursor blink off
call act
call iicp
;***************************************************
;* Lcd data subroutine *
;***************************************************
nou call iict
movlw 0x74
call act
movlw 0x80 ; Co=1, RS=0 just one next command byte
call act
movlw 0x8C ; set CGRAM for characters
call act
movlw 0x40 ; Co=0, RS=1, set instruction register for multiple next data bytes
call act
movlw 0xD4 ; T
call act
movlw 0xE5 ; e
call act
movlw 0xED ; m
call act
movlw 0xF0 ; p
call act
movlw 0xBA ; :
call act
movlw 0xAB ;
btfsc semn,0
addlw 0x02
call act
scrie call rset
movlw 0xCC ;skip rom
call schtx
movlw 0x44 ;convert
call schtx
call halta
call rset
movlw 0xCC ;skip rom
call schtx
movlw 0xBE ;read scratchpad
call schtx
call schrx
call mux
movf dig2,0
addlw 0xB0
call act
movf dig1,0
addlw 0xB0
call act
movlw 0xAC
call act
movf dig3,0
addlw 0xB0
call act
movlw 0x20 ;
call act
movlw 0xC3 ;
call act
call iicp
goto nou
;***************************************************
rset bcf grad
call halte ; 510 us
bsf grad
call usain
call haltd ; 61 us
btfsc grad
bsf PORTB,0
btfss grad
bcf PORTB,0
call halte ; 510us
call usaex
retlw 00
;***************************************************
schtx movwf ratb ;
movlw 0x08
movwf count3
;***************************************************
gbit btfsc ratb,0 ; data reverse flow
call unu
btfss ratb,0
call nul
rrf ratb,F
decfsz count3,F
goto gbit
retlw 00
;***************************************************
schrx movlw 0x08
movwf count3
samp rrf ratb,F
bcf grad
call usain
call haltcc ; 11us
btfsc grad ; data reverse flow
bsf ratb,7
btfss grad
bcf ratb,7
call haltd ; 61 us
call usaex
decfsz count3,F
goto samp
bcf grad
call usain
call haltc ; 11us
btfsc grad ; data bit flow
bsf semn,0
btfss grad
bcf semn,0
call haltd ; 61 us
call usaex
btfsc semn,0
call negativ
movlw 0x00
btfsc ratb,0
addlw 0x05
movwf dig3
rrf ratb,0
andlw 0x7F
movwf ratb
return
;***************************************************
negativ
movf ratb,0
xorlw 0xFF
addlw 0x01
movwf ratb
return
;***************************************************
;***************************************************
unu bcf grad
call haltc ; 11 us
bsf grad
call haltd ; 65 us
retlw 00
;***************************************************
nul bcf grad
call haltc ; 11 us
call haltd ; 65 us
bsf grad
retlw 00
;***************************************************
act movwf transo ; iic data transmission
movlw 0x08
movwf count3
vbit bcf sclk
call haltb
btfsc transo,7
bsf sdta
btfss transo,7
bcf sdta
call haltb
bsf sclk
call haltb
bcf sclk
call haltb
rlf transo,F
decfsz count3,F
goto vbit
call ackp
retlw 00
;***************************************************
iicp bcf sdta ; stop condition module
call haltb
bsf sclk
call haltb
bsf sdta ; stop command
call haltb
bcf sclk
call haltb
retlw 00
;***************************************************
iict bsf sdta ; start condition module
bsf sclk
call haltb
bcf sdta ; start command
call haltb
bcf sclk
call haltb
retlw 00
;***************************************************
ackp bsf sclk ; one clock step for acknowledge (not read)
call haltb
bcf sclk
call haltb
retlw 00
;***************************************************
halta movlw 0x90 ; cca. 800ms delay
movwf count3
r3 movlw 0xFF
movwf count2
r2 call pwmm
decfsz count2,F
goto r2
decfsz count3,F
goto r3
retlw 00
;***************************************************
haltb movlw 0x10
movwf count2
d1 call pwmm
decfsz count2,F
goto d1
retlw 00
;***************************************************
haltc movlw 0x02 ; 11us
movwf count1
w1 decfsz count1,F
goto w1
retlw 00
;***************************************************
haltcc
movlw 0x01 ; 9us
movwf count1
ww1 decfsz count1,F
goto ww1
nop
retlw 00
;***************************************************
haltd call pwmm
call pwmm
call haltc
retlw 00
;***************************************************
;***************************************************
halte movlw 0x14 ; 510 us
movwf count2
w3 call pwmm
decfsz count2,F
goto w3
retlw 00
;***************************************************
;------------------------------------------------------------
pwmm bsf osc
call haltc
bcf osc
call haltc
retlw 00
;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
usaex bsf STATUS,RP0 ;switch to bank 1
movlw 0x00 ; PORTA set to out/inputs
movwf TRISA
bcf STATUS,RP0 ;switch back to bank 0
return
;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
usain bsf STATUS,RP0 ;switch to bank 1
movlw 0x08 ; sdta set to input
movwf TRISA
bcf STATUS,RP0 ;switch back to bank 0
return
;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
usbex bsf STATUS,RP0 ;switch to bank 1
movlw 0x00 ; PORTB set to out/inputs
movwf TRISB
bcf STATUS,RP0 ;switch back to bank 0
return
;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
;***************************************************
mux clrf dig1
clrf dig2
movf ratb,F ; zero bit test if dig=dig=0
btfss STATUS,2
goto calc
goto gatam
calc call digi
decfsz ratb,F
goto calc
gatam return
;***************************************************
digi incf dig1,F
movlw 0x0A
subwf dig1,W
btfss STATUS,2 ;test zero bit
goto gatas
clrf dig1
incf dig2,F
movlw 0x0A
subwf dig2,W
btfss STATUS,2 ;test zero bit
goto gatas
clrf dig2
gatas retlw 00
;***************************************************
end
;============================================================
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