.TH "<avr/io.h>: AVR device-specific IO definitions" 3avr "Wed Jun 4 2014" "Version 1.8.0svn" "avr-libc" \" -*- nroff -*-
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.SH NAME
<avr/io.h>: AVR device-specific IO definitions \- 
.SS "Macros"

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.RI "#define \fB_PROTECTED_WRITE\fP(reg, value)"
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.SH "Detailed Description"
.PP 

.PP
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#include <avr/io\&.h> 

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.PP
.PP
This header file includes the apropriate IO definitions for the device that has been specified by the \fC-mmcu=\fP compiler command-line switch\&. This is done by diverting to the appropriate file \fC<avr/io\fP\fIXXXX\fP\fC\&.h>\fP which should never be included directly\&. Some register names common to all AVR devices are defined directly within \fC<avr/common\&.h>\fP, which is included in \fC<\fBavr/io\&.h\fP>\fP, but most of the details come from the respective include file\&.
.PP
Note that this file always includes the following files: 
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#include <avr/sfr_defs\&.h>
#include <avr/portpins\&.h>
#include <avr/common\&.h>
#include <avr/version\&.h>

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.PP
 See \fB<avr/sfr_defs\&.h>: Special function registers\fP for more details about that header file\&.
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Included are definitions of the IO register set and their respective bit values as specified in the Atmel documentation\&. Note that inconsistencies in naming conventions, so even identical functions sometimes get different names on different devices\&.
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Also included are the specific names useable for interrupt function definitions as documented \fBhere\fP\&.
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Finally, the following macros are defined:
.PP
.IP "\(bu" 2
\fBRAMEND\fP 
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 The last on-chip RAM address\&. 
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.IP "\(bu" 2
\fBXRAMEND\fP 
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 The last possible RAM location that is addressable\&. This is equal to RAMEND for devices that do not allow for external RAM\&. For devices that allow external RAM, this will be larger than RAMEND\&. 
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.IP "\(bu" 2
\fBE2END\fP 
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 The last EEPROM address\&. 
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.IP "\(bu" 2
\fBFLASHEND\fP 
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 The last byte address in the Flash program space\&. 
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.IP "\(bu" 2
\fBSPM_PAGESIZE\fP 
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 For devices with bootloader support, the flash pagesize (in bytes) to be used for the \fCSPM\fP instruction\&.
.IP "\(bu" 2
\fBE2PAGESIZE\fP 
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 The size of the EEPROM page\&. 
.PP

.SH "Macro Definition Documentation"
.PP 
.SS "#define _PROTECTED_WRITE(reg, value)"
Write value \fCvalue\fP to IO register \fCreg\fP that is protected through the Xmega configuration change protection (CCP) mechanism\&. This implements the timed sequence that is required for CCP\&.
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Example to modify the CPU clock: 
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#include <avr/io\&.h>

_PROTECTED_WRITE(CLK_PSCTRL, CLK_PSADIV0_bm);
_PROTECTED_WRITE(CLK_CTRL, CLK_SCLKSEL0_bm);

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.SH "Author"
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Generated automatically by Doxygen for avr-libc from the source code\&.