CONFIG SCL

Action

Overrides the SCL pin assignment from the Option Compiler Settings.

 

 

Syntax

CONFIG SCL = pin

 

 

Remarks

Pin	The port pin to which the I2C-SCL line is connected.

 

When you use different pins in different projects, you can use this statement to override the Options Compiler setting for the SCL pin. This way you will remember which pin you used because it is in your code and you do not have to change the settings from the options. Of course BASCOM-AVR also stores the settings in a project.CFG file.

 

When using the Hardware TWI, you only need CONFIG SCL when you use the I2CINIT statement

 

 

See also

CONFIG SDA , CONFIG I2CDELAY , I2CINIT

 

 

Example

CONFIG SCL = PORTB.5 'PORTB.5 is the SCL line

'-----------------------------------------------------------------------------------------
'name : i2c.bas
'copyright : (c) 1995-2005, MCS Electronics
'purpose : demo: I2CSEND and I2CRECEIVE
'micro : Mega48
'suited for demo : yes
'commercial addon needed : no
'-----------------------------------------------------------------------------------------
 
$regfile = "m48def.dat" ' specify the used micro
$crystal = 4000000 ' used crystal frequency
$baud = 19200 ' use baud rate
$hwstack = 32 ' default use 32 for the hardware stack
$swstack = 10 ' default use 10 for the SW stack
$framesize = 40 ' default use 40 for the frame space
 
'We use here the Software I2C Routines
Config Scl = Portb.4
Config Sda = Portb.5
I2cinit
 
Config I2cdelay = 10 '100KHz
 
Declare Sub Write_eeprom(byval Adres As Byte , Byval Value As Byte)
Declare Sub Read_eeprom(byval Adres As Byte , Value As Byte)
 
Const Addressw = 174 'slave write address
Const Addressr = 175 'slave read address
 
Dim B1 As Byte , Adres As Byte , Value As Byte 'dim byte
 
Call Write_eeprom(1 , 3) 'write value of three to address 1 of EEPROM
Call Read_eeprom(1 , Value) : Print Value 'read it back
Call Read_eeprom(5 , Value) : Print Value 'again for address 5
 
'-------- now write to a PCF8474 I/O expander -------
I2csend &H40 , 255 'all outputs high
I2creceive &H40 , B1 'retrieve input
Print "Received data " ; B1 'print it
End
 
Rem Note That The Slaveaddress Is Adjusted Automaticly With I2csend & I2creceive
Rem This Means You Can Specify The Baseaddress Of The Chip.
 
 
 
'sample of writing a byte to EEPROM AT2404
Sub Write_eeprom(byval Adres As Byte , Byval Value As Byte)
 I2cstart 'start condition
 I2cwbyte Addressw 'slave address
 I2cwbyte Adres 'asdress of EEPROM
 I2cwbyte Value 'value to write
 I2cstop 'stop condition
 Waitms 10 'wait for 10 milliseconds
End Sub
 
 
'sample of reading a byte from EEPROM AT2404
Sub Read_eeprom(byval Adres As Byte , Value As Byte)
 I2cstart 'generate start
 I2cwbyte Addressw 'slave adsress
 I2cwbyte Adres 'address of EEPROM
 I2cstart 'repeated start
 I2cwbyte Addressr 'slave address (read)
 I2crbyte Value , Nack 'read byte
 I2cstop 'generate stop
End Sub
 
' when you want to control a chip with a larger memory like the 24c64 it requires an additional byte
' to be sent (consult the datasheet):
' Wires from the I2C address that are not connected will default to 0 in most cases!
 
' I2cstart 'start condition
' I2cwbyte &B1010_0000 'slave address
' I2cwbyte H 'high address
' I2cwbyte L 'low address
' I2cwbyte Value 'value to write
' I2cstop 'stop condition
' Waitms 10

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