' Name        : ONEWIRE.pbp
' Compiler    : PICBASIC PRO Compiler 2.6
' Assembler   : PM or MPASM
' Target PIC  : 40-pin 16F877A or similar
' Hardware    : Lab-X1
' Oscillator  : 4MHz external
' Keywords    : LCDOUT, OWIN, OWOUT
' Description : PICBASIC PRO program to demonstrate 1-wire temperature
' display with LAB-X1 and DS1820 1-wire temp sensor.
'

temperature  Var Word       ' Temperature storage
count_remain Var Byte       ' Count remaining
count_per_c  Var Byte       ' Count per degree C

DQ Var PORTC.0              ' One-wire data pin

' 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

   ADCON1 = 7                    ' Set PORTA and PORTE to digital
   Low PORTE.2                   ' LCD R/W line low (W)

mainloop:
   OWOut DQ, 1, [$CC, $44]       ' Start temperature conversion

waitloop:
   OWIn DQ, 4, [count_remain]    ' Check for still busy converting
   If count_remain = 0 Then waitloop

   OWOut DQ, 1, [$CC, $BE]       ' Read the temperature
   OWIn DQ, 0, [temperature.LOWBYTE, temperature.HIGHBYTE, Skip 4, count_remain, count_per_c]

   ' Calculate temperature in degrees C to 2 decimal places (not valid for negative temperature)
   temperature = (((temperature >> 1) * 100) - 25) + (((count_per_c - count_remain) * 100) / count_per_c)
   Lcdout $fe, 1, DEC (temperature / 100), ".", DEC2 temperature, " C"

   ' Calculate temperature in degrees F to 2 decimal places (not valid for negative temperature)
   temperature = (temperature */ 461) + 3200
   Lcdout $fe, $c0, DEC (temperature / 100), ".", DEC2 temperature, " F"

   Pause 1000                    ' Display about once a second
   Goto mainloop                 ' Do it forever

   End