'*****************************************************************************
'*
'* Title  : TCN75 digital thermometer
'* Version  : 1.0
'* program code  : BASCOM AVR basic
'* Last updated  : 2002 04 20
'* Target  : AT90S2313
'* Hardware requirements: STK500, LCD interface board, thermometer board with DS1621.
'*
'* DESCRIPTION
'* This program shows the temperature on the LCD interface, the temperature is measured
'* with the TCN75 which has an I2C interface.
'*****************************************************************************

Dim Tempmsb As Byte
Dim Templsb As Byte
Dim Th As Byte
Dim Tl As Byte
Dim Confg As Byte
Dim Count As Byte
Dim Slope As Byte

Config Lcdpin = Pin , Db4 = Portb.3 , Db5 = Portb.2 , Db6 = Portb.1 , Db7 = Portb.0 , E = Portb.6 , Rs = Portb.7

Config Lcd = 16 * 2

$crystal = 10000000
$baud = 9600

Deflcdchar 0 , 14 , 17 , 17 , 17 , 14 , 32 , 32 , 32        'degree
Deflcdchar 1 , 4 , 14 , 31 , 32 , 32 , 32 , 32 , 32         'up
Deflcdchar 2 , 32 , 32 , 32 , 32 , 32 , 31 , 14 , 4         'down
Deflcdchar 3 , 32 , 32 , 32 , 31 , 31 , 32 , 32 , 32        'equal

Config Sda = Portd.3
Config Scl = Portd.2

Cls
Cursor Off

Goto Loop

'write TH
I2cstart
I2cwbyte &H90
I2cwbyte &HA1
I2cwbyte 25
I2cstop
'--------------
'write TL
I2cstart
I2cwbyte &H90
I2cwbyte &HA2
I2cwbyte 20
I2cstop
'--------------
'read TH
I2cstart
I2cwbyte &H90
I2cwbyte &HA1
I2cstop

I2cstart
I2cwbyte &H91
I2crbyte Th , Nack
I2cstop
'--------------
'read TL
I2cstart
I2cwbyte &H90
I2cwbyte &HA2
I2cstop

I2cstart
I2cwbyte &H91
I2crbyte Tl , Nack
I2cstop
'--------------
'read config
I2cstart
I2cwbyte &H90
I2cwbyte &HAC
I2cstop

I2cstart
I2cwbyte &H91
I2crbyte Confg , Nack
I2cstop
'--------------
Goto Loop
'read counter
Readcnt:
I2cstart
I2cwbyte &H90
I2cwbyte &HA8
I2cstop

I2cstart
I2cwbyte &H91
I2crbyte Count , Nack
I2cstop
Return
'--------------
'read slope
Readslp:
I2cstart
I2cwbyte &H90
I2cwbyte &HA9
I2cstop

I2cstart
I2cwbyte &H91
I2crbyte Slope , Nack
I2cstop
Return
'--------------
'read config
I2cstart
I2cwbyte &H90
I2cwbyte &HAC
I2cstop

I2cstart
I2cwbyte &H91
I2crbyte Confg , Nack
I2cstop

'start convert
I2cstart
I2cwbyte &H90
I2cwbyte &H00
I2cstop
'-------------

Loop:

I2cstart
I2cwbyte &H90
I2cwbyte &H01
I2cstop

I2cstart
I2cwbyte &H90
I2cwbyte &H18
I2cstop

'read temperature
I2cstart
I2cwbyte &H90
I2cwbyte &H00
I2cstop

I2cstart
I2cwbyte &H91
I2crbyte Tempmsb , Ack
I2crbyte Templsb , Nack
I2cstop

Wait 1

If Templsb = 128 Then Templsb = 5 Else Templsb = 0
Locate 1 , 1
Lcd "TCN75 Thermometer"
Locate 2 , 1
Lcd "**** " ; Tempmsb ; "," ; Templsb ; Chr(0) ; "C" ; " ****"
Print Tempmsb ; "," ; Templsb
Goto Loop