;------ <META http-equiv="Bulletin-Text" content="ical-yahoo-"> ----------------------------------------------------------------; ; THERM4M.ASM Shows Temperature from Thermistor on LCD, 4 MHz clock ; ;----------------------------------------------------------------------; ; 555 V+ PIC16F84 ; .----------. | .-----------. ; gnd ---|gnd Vcc|--- V+ [R] -|RA2 RA1|----[LCD E] ; .-|trig dis|----------| -|RA3 RA0|----[LCD RS] ; RA4<--|-|out thres|--.--{r}--' in>-|RA4 OSC1|--|X|__ gnd ; V+ --|-|rst cont| |--|<---' V+--|MCLR OSC2|--|X| X = 4 MHz ; | '----------' | gnd--|Vss Vdd|--- V+ cer. res. ; '---------------' [LCD D4]----|RB0 RB7|- ; | C [LCD D5]----|RB1 RB6|- V+ = 4.5 or 5V ; '---||---gnd [LCD D6]----|RB2 RB5|---[PB]--- gnd ; C = 0.03 mfd [LCD D7]----|RB3 RB4|---[PB]--- gnd ; -{r}- = 33K '-----------' ; -|<- = 1n4148 [R] = Thermistor -[PB]- = pushbutton ; LCD pin connections: ; 1 - gnd ground 2 - Vcc V+ 3 - contrast 10K pot V+ & gnd ; 4 - RS RA0 PIC(17) 5 - RW gnd 6 - E RA1 PIC(18) ; 7 - D0 gnd 8 - D1 gnd 9 - D2 gnd 10 - D3 gnd ; 11 - D4 RB0 (6) 12 - D5 RB1 (7) 13 - D6 RB2 (8) 14 - D7 (9) LIST P=16F84 ; 16F84 Runs at 4 MHz INCLUDE "p16f84.inc" __CONFIG _PWRTE_ON & _XT_OSC & _WDT_OFF ; uses 4 MHz crystal ERRORLEVEL -224 ; supress annoying message from tris ERRORLEVEL -302 ; supress message from page change ; Define Information #DEFINE RS PORTA, 0 ; RA0 is RS line of LCD #DEFINE E PORTA, 1 ; RA1 is E line of LCD ; RB0-RB3 are D4-D7 of LCD ; Macro EStrobe MACRO ; Strobe the "E" Bit bsf E bcf E ENDM CBLOCK 0CH Temp ; a temporary variable count ; counter cntmsec ; used in counting milliseconds bin ; binary number to be converted to BCD hundreds ; BCD hundreds result tens_and_ones ; BCD tens and ones result savetmr0 ; used to save value of tmr0 dispvalue ; used to hold temperature displayed ENDC ORG 0 ; start at location 0 goto main ; jump over to main routine ;----------------------------------------------------------------------; ; Data for message to be output ; ;----------------------------------------------------------------------; shomsg: ; Message to Output addwf PCL, f ; Output the Characters m0 dt "TMR0 Value:", 0 m1 dt "Temperature", 0 ;----------------------------------------------------------------------; ; Ratios of Prescaler ; ;----------------------------------------------------------------------; preratio: addwf PCL, f ; select offset using W dt D'2',D'4',D'8',D'16',D'32',D'64',D'128' ;----------------------------------------------------------------------; ; Initialize the ports ; ;----------------------------------------------------------------------; Init: clrf PORTA clrf PORTB movlw B'00010000' ; RA4 input, others outputs tris PORTA movlw B'00110000' ; RB4, RB5 input, others outputs tris PORTB movlw B'00100011' ; pull-ups enabled ; prescaler assigned to RA4 ; prescaler set to 1:16 option return ;----------------------------------------------------------------------; ; Initialize the LCD ; ;----------------------------------------------------------------------; initlcd: movlw D'40' call nmsec ; Wait 40 msecs before Reset bcf RS ; send an 8 bit instruction movlw 0x03 ; Reset Command call NybbleOut ; Send the Nybble call Dlay5 ; Wait 5 msecs before Sending Again EStrobe call Dlay160 ; Wait 160 usecs before Sending 2nd Time EStrobe call Dlay160 ; Wait 160 usecs before Sending 3rd Time bcf RS ; send an 8 bit instruction movlw 0x02 ; Set 4 Bit Mode call NybbleOut call Dlay160 movlw 0x028 ; 4 bit, 2 Line, 5x7 font call SendINS movlw 0x010 ; display shift off call SendINS movlw 0x001 ; Clear the Display RAM call SendINS call Dlay5 ; Note, Can take up to 4.1 msecs movlw 0x006 ; increment cursor call SendINS movlw 0x00C ; display on cursor off call SendINS return ;----------------------------------------------------------------------; ; Send the character in W out to the LCD ; ;----------------------------------------------------------------------; SendASCII addlw '0' ; Send nbr as ASCII character SendCHAR ; Send the Character to the LCD movwf Temp ; Save the Temporary Value swapf Temp, w ; Send the High Nybble bsf RS ; RS = 1 call NybbleOut movf Temp, w ; Send the Low Nybble bsf RS call NybbleOut return ;----------------------------------------------------------------------; ; Send an instruction in W out to the LCD ; ;----------------------------------------------------------------------; SendINS ; Send the Instruction to the LCD movwf Temp ; Save the Temporary Value swapf Temp, w ; Send the High Nybble bcf RS ; RS = 0 call NybbleOut movf Temp, w ; Send the Low Nybble bcf RS call NybbleOut return ;----------------------------------------------------------------------; ; Send the nibble in W out to the LCD ; ;----------------------------------------------------------------------; NybbleOut ; Send a Nybble to the LCD movwf PORTB EStrobe ; Strobe out the LCD Data call Dlay160 ; delay for 160 usec return ;----------------------------------------------------------------------; ; Output the message on the LCD ; ;----------------------------------------------------------------------; OutMessage: movwf FSR ; Point at first letter OutLoop: movf FSR, w ; Get pointer into W incf FSR, f ; Set up for next letter call shomsg ; Get character to output iorlw 0 ; At the End of the Message? btfsc STATUS, Z ; Skip if not at end return ; Yes - Equal to Zero call SendCHAR ; Output the ASCII Character goto OutLoop ; Get the next character ;----------------------------------------------------------------------; ; Change binary nbr in bin to BCD ; ;----------------------------------------------------------------------; binary_to_bcd ; by Scott Dattalo clrf hundreds swapf bin, W addwf bin, W andlw B'00001111' skpndc addlw 0x16 skpndc addlw 0x06 addlw 0x06 skpdc addlw -0x06 btfsc bin,4 addlw 0x16 - 1 + 0x6 skpdc addlw -0x06 btfsc bin,5 addlw 0x30 btfsc bin, 6 addlw 0x60 btfsc bin,7 addlw 0x20 addlw 0x60 rlf hundreds, f btfss hundreds, 0 addlw -0x60 movwf tens_and_ones btfsc bin,7 incf hundreds, f return ;----------------------------------------------------------------------; ; time delay routines ; ;----------------------------------------------------------------------; Dlay160: movlw D'40' ; delay about 160 usec,(4/loop ) micro4 addlw H'FF' ; subtract 1 from 'W' btfss STATUS,Z ; skip when you reach zero goto micro4 ; more loops return Dlay5: movlw 5 ; delay for 5 milliseconds goto $ + 2 msec250: movlw D'250' ; delay for 250 milliseconds ;*** N millisecond delay routine *** nmsec: movwf cntmsec ; delay for N (in W) millisec msecloop: movlw D'248' ; 1 usec for load call micro4 ; this instruction takes 995 usec nop ; 1 usec decfsz cntmsec,f ; 1 usec, (2 if skip taken) goto msecloop ; 2 usec here makes 995+5=1 msec return ;----------------------------------------------------------------------; ; Display binary value in W in decimal ; ; ;----------------------------------------------------------------------; DispDec movwf bin call binary_to_bcd movf hundreds, W call SendASCII swapf tens_and_ones, W andlw H'F' call SendASCII movf tens_and_ones, W andlw H'F' call SendASCII return ;----------------------------------------------------------------------; ; The Main routine ; ;----------------------------------------------------------------------; main: call Init ; initialize ports, set up timer call initlcd ; initialize the LCD movlw H'80' ; position at 1st line column 0 call SendINS movlw m0 -2 ; send 'TMR0 Value:' message call OutMessage movlw H'C0' call SendINS ; position at 2nd line column 0 movlw m1 -2 ; send 'Temperature:' message call OutMessage sholoop: movlw H'8C' ; position at 1st line column 12 call SendINS bcf INTCON, T0IF ; clear timer zero interrupt flag clrf TMR0 ; zero TMR0 call msec250 ; wait a total of one second call msec250 call msec250 call msec250 movf TMR0, W ; retrieve timer zero movwf savetmr0 ; save the value btfsc INTCON, T0IF ; check if timer overflowed goto overload ; yes, display 'OVR' call DispDec ; display TMR0 value movlw H'CD' ; position at 2nd line column 13 call SendINS movlw 2 ; set up PCLATH to page 2 movwf PCLATH movlw D'32' ; 1st table value is for tmr0 = 32 subwf savetmr0, W ; subtract 32 from tmr0 value call temptable ; get temperature movwf dispvalue ; save it in display value swapf dispvalue, W ; get hi nibble in W andlw H'0F' ; lowest 4 bits call SendASCII ; display it movf dispvalue, W ; get lo nibble in W andlw H'0F' ; lowest 4 bits call SendASCII ; display it goto sholoop ; repeat forever overload movlw 'O' ; output 'OVR' call SendCHAR movlw 'V' call SendCHAR movlw 'R' call SendCHAR goto sholoop ; and continue org H'200' temptable: ; get temperature to display addwf PCL, f dt 11,12,12,13,14,14,15,16,16,17,18,18,19,20,20,21,22,22,23,24,24,25 dt 26,26,27,27,28,29,29,30,31,31,32,32,33,34,34,35,35,36,36,37,38,38 dt 39,39,40,40,41,41,42,42,43,44,44,45,45,46,46,47,47,48,48,49,49,50 dt 50,51,51,52,52,53,53,54,54,54,55,55,56,56,57,57,58,58,59,59,59,60 dt 60,61,61,62,62,63,63,63,64,64,65,65,65,66,66,67,67,68,68,68,69,69 dt 70,70,70,71,71,71,72,72,73,73,73,74,74,75,75,75,76,76,76,77,77,78 dt 78,78,79,79,79,80,80,81,81,81,82,82,82,83,83,83,84,84,84,85,85,85 dt 86,86,87,87,87,88,88,88,89,89,89,90,90,90,91,91,91,92,92,92,93,93 dt 93,94,94,95,95,95,96,96,96,97,97,97,98,98,98,99,99,99,00,00,00,01 dt 01,01,02,02,03,03,03,04,04,04,05,05,05,06,06,06,07,07,08,08,08,09 dt 09,09,10,10 end
file: /Techref/piclist/cheapic/therm4m.asm, 13KB, , updated: 2005/8/20 04:27, local time: 2024/8/14 23:32,
owner: ical-yahoo-,
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