LCD显示的温度表的设计

1、Temperature Display661827TLC5553645RA3RAORA4OSC1MCLRSC2VssVddRBORB7RB1RB6RB2RB5PIC16F84RB3RB4o 1 EDD ooo6 DLCD display of TemperatureTHERM.ASM Shows Temperature from Thermistor on LCDLIST P=16F84;16F84 Runs at 4 MHzINCLUDE Hpl6f84.incnCONFIG PWRTE ON & LP OSC & WDT OFF ; uses 32.768 kHz crystalERROR

2、LEVEL -224; supress annoying message because of trisERRORLEVEL -302; supress message because of page change;Define Information#DEFTNE RS PORTA, 0#DEFINE E PORTA, 1;Macro;RAO is RS line of LCD;RAI is E line of LCD;RB0-RB3 are D4-D7 of LCDEStrobe MACRO; Strobe the nEn Bitbsf E bcf E ENDMCBLOCKOCHTemp;

3、a temporary variablecount;counterbin;binary number to be converted to BCDhundreds;BCD hundreds resulttens_and_ones;BCD tens and ones resultsavetmrO;used to save value of tmrOdispvalue;used to hold temperature to be displayedtableindex;points to table value to displayENDCORG 0; start at location 0got

4、o main; jump over to main routineData for message to be output; Message to Output; Output the Charactersshomsg:addwf PCL, f mO dtnTMR0 Value:H,0ml dtTemperature11,0Ratios of Prescalerpreratio:addwf PCL, f; select offset using Wdt D2,D4,D8,D16,D32,DD4,D128Initialize the portsInit:clrf PORTAclrf PORTB

5、movlw B WO 10000, tris PORTAmovlw BOO 110000tris PORTBmovlw BOO 100011,optionreturn;RA4 input, others outputs;RB4, RB5 input, others outputs;pull-ups enabled;prescaler assigned to RA4;prescaler set to 1:16initlcd:movlw D40 call nmsec bcf RS movlw 0 x03 call NybbleOut call Dlay5 EStrobe nop nop EStro

6、benop nop bcf RS movlw 0 x02 call NybbleOutInitialize the LCD; Wait 40 msecs before Reset; send an 8 bit instruction;Reset Command;Send the Nybble; Wait 5 msecs before Sending Again; Wait 244 usees before Sending the Second Time; Wait 244 usees before Sending the Third Time;send an 8 bit instruction

7、;Set 4 Bit Modenop nop movlw 0 x028 call SendINS movlw 0 x010 call SendINS movlw 0 x001 call SendINS call Dlay5 movlw 0 x006 call SendINS movlw OxOOC call SendINS return; 4 bit, 2 Line, 5x7 font; display shift off;Clear the Display RAM; Note, Can take up to 4.1 msecs;increment cursor; display on cur

8、sor offSend the character in W out to the LCDSendASCIIaddlw OSendCHAR movwf Temp swapf Temp, w bsf RS call NybbleOut movf Temp, w bsf RS call NybbleOut returnSend nbr as ASCII character;Send the Character to the LCD;Save the Temporary Value;Send the High Nybble;RS= 1;Send the Low NybbleSend an instr

9、uction in W out to the LCDSendINSmovwf Temp swapf Temp, wbcf RScall NybbleOut movf Temp, w bcf RScall NybbleOut return; Send the Instruction to the LCD;Save the Temporary Value;Send the High Nybble;RS = 0;Send the Low NybbleSend the nibble in W out to the LCDNybbleOut; Send a Nybble to the LCDmovwf

10、PORTB EStrobe; Strobe out the LCD Datanop nopreturnOutput the message on the LCDOutMessage:movwfFSRPoint at first letterOutLoop:movfincfcalliorlwbtfscFSR, wFSR, f shomsg 0STATUS, Zreturn call; Get pointer into W; Set up for next letter; Get character to output; At the End of the Message?; Skip if no

11、t at end; Yes - Equal to ZerogotoSendCHAROutLoop; Output the ASCII CharacterGet the next characterChange binary nbr in bin to BCDbinary_to_bcdbinary_to_bcd;by Scott Dattaloclrf hundreds swapf bin, W addwf bin, W andlwBOOOOllir skpndcaddlw 0 x16 skpndcaddlw 0 x06addlw 0 x06 skpdc addlw -0 x06 btfsc b

12、in,4addlw Ox 16 - 1 + 0 x6 skpdcaddlw -0 x06btfsc bin,5 addlw 0 x30btfsc bin, 6 addlw 0 x60btfsc bin,7addlw 0 x20addlw 0 x60 rlf hundreds, f btfss hundreds, 0addlw -0 x60 movwf tens_and_ones btfsc bin,7incf hundreds, f returnDelay routinemsec250 movlw 0goto $+2DIay5 movlw 5 nmsec:nopnopnopnop addlw

13、HFF btfss STATUS, Z goto nmsec return;250 msec delay (adjusted to try and;allow for 2.5% low loop time);delay for 5 milliseconds;delay for # msec in W on entry;each nop is 0.122 milliseconds;each total loop is 8 X 0.122 = 0.976 msec;same as subtracting 1 from W;skip if result is zero;this is 2 X 0.1

14、22 msec;back to calling pointDisplay binary value in W in decimalDispDecmovwf bincall binary_to_bcd movf hundreds, W call SendASCII swapf tens_and_ones, W andlw HFcall SendASCIImovf tens_and_ones, W andlw HFcall SendASCII returnThe Main routinemain:call Init call initlcd movlw H80 call SendINS movlw

15、 mO -2 call OutMessage movlw HCO, call SendINS movlw ml -2 call OutMessage sholoop:movlw H8Ccall SendINS;initialize ports, set up timer;initialize the LCD;position at 1st line column 0;send *TMR0 Value: message;position at 2nd line column 0;send Temperature:* message;position at 1st line column 12;c

16、lear timer zero interrupt flag;zero TMRO;wait a total of one second;retrieve timer zero;save the value;check if timer overflowed;yes, display OVR1;display TMRO value;position at 2nd line column 12;set up PCLATH to page 2;1 st table value is for tmrO = 64;subtract 64 from tmrO value;get 1st two digit

17、s of temperature;save it in display value;get hi nibble in W;lowest 4 bits;display it;get lo nibble in W;lowest 4 bits;display it;send decimal point;set up for second table, (page 3);get decimal point;display it;repeat forever;output OVER;and continuebcf INTCON, TOIF clrfTMRO call msec250 call msec2

18、50 call msec250 call msec250 movfTMRO, W movwf savetmrO btfsc INTCON, TOIF goto overload call DispDec movlw HCC call SendINS movlw 2movwf PCLATH movlw D64subwf savetmrO, W movwf tableindex call temptablei movwf dispvalue swapf dispvalue, W andlw HOF call SendASCII movf dispvalue, W andlw HOF call Se

19、ndASCII movlwcall SendCHAR movlw 3movwf PCLATH movf tableindex, W call temptable2 call SendASCII goto sholoop overloadmovlw O call SendCHAR movlw V call SendCHAR movlw E* call SendCHAR movlw R, call SendCHAR movlw call SendCHAR goto sholooporg H20(T temptablei:; get temperature to displayaddwf PCL,

20、fdt 33,34,34,35,35,36,36,37,37,38,38,39,39,40,40,40,41,41,42,42,43 dt 43,44,44,45,45,46,46,46,47,47,48,48,49,49,50,50,50,51,51,52,52 dt 53,53,53,54,54,55,55,56,56,56,57,57,58,58,58,59,59,60,60,60,61 dt 61,62,62,62,63,63,64,64,64,65,65,66,66,66,67,67,67,68,68,69,69 dt 69,70,70,70,71,71,72,72,72,73,73,73,74,74,74,75,75,75,76,76,77 dt 77,77,78,78,78,79,79,79,80,