avr-libc  2.0.0
Standard C library for AVR-GCC

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xmega.h
1 /* Copyright (c) 2012 Joerg Wunsch
2  All rights reserved.
3 
4  Redistribution and use in source and binary forms, with or without
5  modification, are permitted provided that the following conditions are met:
6 
7  * Redistributions of source code must retain the above copyright
8  notice, this list of conditions and the following disclaimer.
9 
10  * Redistributions in binary form must reproduce the above copyright
11  notice, this list of conditions and the following disclaimer in
12  the documentation and/or other materials provided with the
13  distribution.
14 
15  * Neither the name of the copyright holders nor the names of
16  contributors may be used to endorse or promote products derived
17  from this software without specific prior written permission.
18 
19  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
23  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  POSSIBILITY OF SUCH DAMAGE. */
30 
31 /* $Id: xmega_8h_source.html,v 1.1.1.2 2016/02/09 07:13:39 joerg_wunsch Exp $ */
32 
33 /*
34  * This file is included by <avr/io.h> whenever compiling for an Xmega
35  * device. It abstracts certain features common to the Xmega device
36  * families.
37  */
38 
39 #ifndef _AVR_XMEGA_H
40 #define _AVR_XMEGA_H
41 
42 #ifdef __DOXYGEN__
43 /**
44  \def _PROTECTED_WRITE
45  \ingroup avr_io
46 
47  Write value \c value to IO register \c reg that is protected through
48  the Xmega configuration change protection (CCP) mechanism. This
49  implements the timed sequence that is required for CCP.
50 
51  Example to modify the CPU clock:
52  \code
53  #include <avr/io.h>
54 
55  _PROTECTED_WRITE(CLK_PSCTRL, CLK_PSADIV0_bm);
56  _PROTECTED_WRITE(CLK_CTRL, CLK_SCLKSEL0_bm);
57  \endcode
58  */
59 #define _PROTECTED_WRITE(reg, value)
60 #else /* !__DOXYGEN__ */
61 #define _PROTECTED_WRITE(reg, value) \
62  __asm__ __volatile__("out %[ccp], %[ccp_ioreg]" "\n\t" \
63  "sts %[ioreg], %[val]" \
64  : \
65  : [ccp] "I" (_SFR_IO_ADDR(CCP)), \
66  [ccp_ioreg] "d" ((uint8_t)CCP_IOREG_gc), \
67  [ioreg] "n" (_SFR_MEM_ADDR(reg)), \
68  [val] "r" ((uint8_t)value))
69 #endif /* DOXYGEN */
70 
71 #endif /* _AVR_XMEGA_H */