Read Manufacture ID

Read Device ID

Read Status byte 1

Read Status byte 2

Read MAX1668 Local Temperature

Set remote DX1 Thigh limit

Set remote DX1 Tlow limit

Read Remote DX1 Thigh limit

Read Remote DX1 Tlow limit

Read Remote DX1 temperature 10 times with a 1sec. interval

There is much more possible with the MAX1668, the MAX1668 can generate an interrupt if a temperature is outside Thigh or Tlow limits for example. Consult the datasheet for an overview of all available commands.

Bascom example program :

'**********************************************************************
' Application Note: Using the MAX1668
'-----------------------------------------------------
'
' Program-ID.: MAX1668.bas.
' Date...... : 22 / 05 / 2005
' Description: Example program for MAX1668 Multichannel Remote/Local
' Temperature Sensors
' write and read routines.
'
' Author : Roland van leusden (sayang@zonnet.nl).
'
' Setup for the AT90S2313 using portd.6 for SDA and Portd.5 for SCL.
' (Futurlec ET-JRAVR board)
' See page 1 from MAX1668 datasheet for shematic. (www.maxim-ic.com)
'
' This program provides an example for writing to and reading from
' a MAX1668 device wired with AO,A1 open.
'
'
'**********************************************************************
$regfile = "2313def.dat" ' Change for your AVR.
$crystal = 4000000 ' 4 MHz Crystal.
$baud = 19200  ' Output at 19200 baud.

'**********************************************************************
'** Set up Data Direction Registers and ports - Do this before defining I2C pins!
'**********************************************************************
' Port B
Portb = &B0000_0000 ' Set All Port Pins Low
Ddrb = &B1111_1111 ' Set Unused Pins As Outputs.
' Port D
Portd = &B0000_0000 ' All low - with push-pull output
Ddrd = &B1111_1111 ' with internal pullups.

'**********************************************************************
'** Define and initialize I2C pins **
'**********************************************************************
Config Sda = Portd.6 ' I2C Data.
Config Scl = Portd.5  ' I2C Clock.

'**********************************************************************

'**********************************************************************
'
'** Declare subroutines **
'**********************************************************************
'
' This subroutine writes data to the I2C MAX1668.
'
Declare Sub I2c_max1668_write(byval Cmd As Byte , Byval Msb As Byte)
'
' This subroutine reads data from the I2C MAX1668.
'
Declare Sub I2c_max1668_read(byval Cmd As Byte , Msb As Byte)
'**********************************************************************
'** Define working variables and constants **
'**********************************************************************

Dim Max1668_adress_w As Byte
Max1668_adress_w = &H54 'A1 & A0 open, see datasheet

Dim Max1668_adress_r As Byte
Max1668_adress_r = &H55 'A1 & A0 open, see datasheet

Dim Counter_1 As Byte
Dim Cmd As Byte
Dim Msb As Byte



'**********************************************************************
'** Actual work starts here. **
'**********************************************************************


Main:

Msb = &H00
Call I2c_max1668_read(&Hfe , Msb) ' Read MSB
Print "Manufacture ID : " ; Hex(msb) ' MSB to serial port

Msb = &H00
Call I2c_max1668_read(&Hff , Msb)  ' Read MSB
Print "Device ID : " ; Hex(msb) ' MSB to serial port

Msb = &H00
Call I2c_max1668_read(&H05 , Msb) ' Read MSB
Print "Status byte 1 : " ; Bin(msb) ' MSB to serial port

Msb = &H00
Call I2c_max1668_read(&H06 , Msb) ' Read MSB
Print "Status byte 2 : " ; Bin(msb) ' MSB to serial port

Msb = &H00
Call I2c_max1668_read(&H00 , Msb) ' Read MSB
Print "MAX1668 Local Temperature: " ; Msb ' MSB to serial port

Msb = &H09
Call I2c_max1668_write(&H15 , Msb) ' Write remote DX1 THIGH limit

Msb = &H00
Call I2c_max1668_write(&H16 , Msb) ' Write remote DX1 Tlow limit

Msb = &H00
Call I2c_max1668_read(&H0a , Msb) ' Read MSB
Print "Remote DX1 Thigh limit: " ; Msb ' MSB to serial port

Msb = &H00
Call I2c_max1668_read(&H0b , Msb) ' Read MSB
Print "Remote DX1 Tlow limit: " ; Msb ' MSB to serial port

Counter_1 = 0

Do

Msb = &H00
Call I2c_max1668_read(&H01 , Msb) ' Read MSB
Print "Remote DX1 temperature: " ; Msb ' MSB to serial port
Wait 1
Counter_1 = Counter_1 + 1

Loop Until Counter_1 = 10

End 'end program




'**********************************************************************
'** Define Subroutines **
'**********************************************************************
Sub I2c_max1668_write(byval Cmd As Byte , Msb As Byte)
' Writes data to the I2C MAX1668.

 I2cstart 'Generate A Start Condition
 I2cwbyte Max1668_adress_w 'Transmit The "ADDRESS and WRITE" Byte
 I2cwbyte Cmd  'Transmit The Command Byte
 I2cwbyte Msb 'Transmit Data Byte
 I2cstop 'Generate a STOP condition
 'Waitus 50  'Some delay may be necessary for back to back transmitions

End Sub

Sub I2c_max1668_read(byval Cmd As Byte , Msb As Byte)
' Read data from the I2C MAX1668

 I2cstart 'Generate START condition
 I2cwbyte Max1668_adress_w 'Transmit The "ADDRESS and WRITE" Byte
 I2cwbyte Cmd 'Transmit The Command Byte
 I2cstart  'Generate a REPEATED-START condition
 I2cwbyte Max1668_adress_r 'Transmit ADDRESS with READ command
 I2crbyte Msb , Nack 'Receive DATA byte (MSB) and don't acknowledge
 I2cstop 'Generate a STOP condition

End Sub

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