' Name : VBARX.pbp ' Compiler : PICBASIC PRO Compiler 2.6 ' Assembler : PM or MPASM ' Target PIC : 40-pin 16F877 or similar ' Hardware : LAB-X1 Experimenter Board ' Oscillator : 4MHz external ' Keywords : ADCIN, LCDOUT, REP ' Description : PICBASIC PRO program to measure voltage (0-5VDC) ' and display on LCD with 2 decimal places. A 60 segment bargraph ' is also displayed using custom LCD characters. ' ' This program uses the */ operator to scale the ADC result from 0-1023 ' to 0-500. The */ performs a divide by 256 automatically, allowing math ' which would normally exceed the limit of a word variable. ' Connect analog input to channel-0 (RA0) ' Define LOADER_USED to allow use of the boot loader. ' This will not affect normal program operation. Define LOADER_USED 1 ' Define LCD registers and bits Define LCD_DREG PORTD Define LCD_DBIT 4 Define LCD_RSREG PORTE Define LCD_RSBIT 0 Define LCD_EREG PORTE Define LCD_EBIT 1 ' Define ADCIN parameters Define ADC_BITS 10 ' Set number of bits in result Define ADC_CLOCK 3 ' Set clock source (3=rc) Define ADC_SAMPLEUS 50 ' Set sampling time in uS ' Declare variables adval VAR WORD ' Create adval to store result fullbars VAR BYTE ' Number of full bars at left of graph barval VAR BYTE ' Value passed to bargraph routine partbar VAR BYTE ' ASCII code for partial bar character pad VAR BYTE ' Number of spaces to pad to the right of graph TRISA = %11111111 ' Set PORTA to all input ADCON1 = %10000010 ' Set PORTA analog and right justify result ' PORTE remains digital to allow operation of the LCD Low PORTE.2 ' LCD R/W line low (W) Pause 500 ' Wait .5 second ' Load the custom characters to LCD CGRAM. The blank at $0 makes the graphing math work faster. LCDOut $FE,64,REP $0\8 ' Load blank character (ascii $0) LCDOut $0,REP $10\6,$0 ' Load | character (ascii $1) LCDOut $0,REP $14\6,$0 ' Load || character (ascii $2) LCDOut $0,REP $15\6,$0 ' Load ||| character (ascii $3) LCDOut $FE, 1 ' Clear the display mainloop: ADCIN 0, adval ' Read channel 0 to adval (0-1023) adval = (adval */ 500)>>2 ' equates to: (adval * 500)/1024 LCDOut $FE,2,"DC Volts= ",DEC (adval/100),".", DEC2 adval ' Display the decimal value barval = (adval/9)+1 ' Scale 0-500 to 60 segment bargraph (1-56) GoSub bargraph ' Update bargraph with new barval GoTo mainloop ' Do it forever bargraph: fullbars = (barval MIN 60)/3 ' Calculate number of full bars (|||). ' partbar holds the ascii code for the partial bar character: $0=" ", $1="|", or $2="||" partbar = (barval MIN 60) // 3 ' Calculate ascii code for partial bar character pad = 19 - fullbars ' Number of spaces to fill display width. LCDOut $fe,$c0, REP $3\fullbars, partbar, REP " "\pad ' Display the bar on second line Return End