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== (**COPIED FROM ENGLISH PAGE**) === <span class="f_Header">Action</span> =

Configure the TWI (two wire serial interface).

<span style="font-family: Arial;">&nbsp;</span>

<span style="font-family: Arial;">&nbsp;</span>

= <span class="f_Header">Syntax</span> =

<span class="f_Syntax">CONFIG TWI&nbsp;</span>= clockspeed

<span class="f_Syntax">CONFIG TWIC | TWID | TWIE | TWIF&nbsp;</span>= clockspeed

&nbsp;

<span style="font-family: Arial;">(Config TWI is for ATMEGA and Config TWI</span><span style="font-family: Arial; font-weight: bold;">X</span><span style="font-family: Arial;">&nbsp;is for ATXMEGA chips)</span>

<span style="font-family: Arial;">&nbsp;</span>

= <span class="f_Header">Remarks</span> =
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| valign="top" width="24%" style="width: 112px; border: 1px solid rgb(0, 0, 0);" | 
clockspeed

| valign="top" width="100%" style="width: 364px; border: 1px solid rgb(0, 0, 0);" | 
The desired clock frequency for SCL

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<span style="font-family: Arial;">&nbsp;</span>

<span style="font-family: Arial;">&nbsp;</span>

CONFIG TWI will set TWSR pre scaler bits 0 and 1, and TWBR depending on the used&nbsp;[[$CRYSTAL]]&nbsp;frequency and the desired SCL clock speed.

Typical you need a speed of 400 KHz. Some devices will work on 100 KHz as well.

<span style="font-family: Arial;">&nbsp;</span>

When TWI is used in SLAVE mode, you need to have a faster clock speed as the master.

&nbsp;

= <span class="f_Header">XMEGA</span> =

The XMEGA can contain up to 4 TWI units. When not specifying TWIC, TWID, TWIE or TWIF, the&nbsp;<span style="font-weight: bold;">TWIC</span>&nbsp;will be used as &nbsp;the default.

You MUST dimension a variable named&nbsp;<span style="font-weight: bold;">TWI_START</span>&nbsp;as a byte. It is used by the xmega TWI library code. Without it, you will get an error.

&nbsp;

There are 2 manuals available from ATMEL for every ATXMEGA Chip

&nbsp;
<div style="padding: 0px; margin: 0px;">
{| border="0" cellpadding="0" cellspacing="0"
|- valign="baseline" style="vertical-align: baseline;"
| width="15" | <span style="font-size: 10pt;">1.</span>
| One Family Manual like for example for a ATXMEGA128<span style="font-weight: bold;">A</span>1 it is Atmel AVR XMEGA&nbsp;<span style="font-weight: bold;">A</span>&nbsp;Manual
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{| border="0" cellpadding="0" cellspacing="0"
|- valign="baseline" style="vertical-align: baseline;"
| width="15" | <span style="font-size: 10pt;">2.</span>
| Another Manual for the single chips like for example for an ATXMEGA128A1 it is the ATxmega64A1/128A1/192A1/256A1/384A1 Manual. In this Manual you find for example the Alternate Pin Functions. So you can find which Pin on Port C is the SDA and SCL Pin when you want to use the I2C/TWI Interface of this Port.
|}
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<span style="font-family: Arial;">&nbsp;</span>

<span style="font-family: Arial;">&nbsp;</span>

[[File:Notice.jpg|left|Notice.jpg]]&nbsp;It is important that you specify the proper crystal frequency. Otherwise it will result in a wrong TWI clock frequency.

<span style="font-family: Arial;">&nbsp;</span>

<span style="font-family: Arial;">&nbsp;</span>

= <span class="f_Header">See also</span> =

[[$CRYSTAL]]&nbsp;,&nbsp;[[OPEN]]

<span style="font-family: Arial;">&nbsp;</span>

<span style="font-family: Arial;">&nbsp;</span>

= <span class="f_Header">Example</span> =

<br/><source lang="bascomavr">
'-----------------------------------------------------------------------
' (c) 2004 MCS Electronics
' This demo shows an example of the TWI
' Not all AVR chips have TWI (hardware I2C)
'------------------------------------------------------------------------
 
'The chip will work in TWI/I2C master mode
'Connected is a PCF8574A 8-bits port extender
 
 
$regfile="M8def.dat"' the used chip
$crystal= 4000000 ' frequency used
$baud= 19200 ' baud rate
 
 
$lib"i2c_twi.lbx"' we do not use software emulated I2C but the TWI
 
Config Scl =Portc.5 ' we need to provide the SCL pin name
Config Sda =Portc.4 ' we need to provide the SDA pin name
 
'On the Mega8, On the PCF8574A
'scl=PC5 , pin 28 pin 14
'sda=PC4 , pin 27 pin 15
 
 
I2cinit' we need to set the pins in the proper state
 
 
Config Twi = 100000 ' wanted clock frequency
'will set TWBR and TWSR
'Twbr = 12 'bit rate register
'Twsr = 0 'pre scaler bits
 
Dim B AsByte, X AsByte
Print"TWI master"
Do
Incr B ' increase value
I2csend&B01110000 , B ' send the value
Print"Error : ";Err' show error status
I2creceive&B01110000 , X ' get a byte
Print X ;" ";Err' show error
Waitms 500 'wait a bit
Loop
End
</source><br/>{{Languages}}

[[Category:BASCOM Language Reference/de]]