Contiki 2.5
spi.h
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2010, Swedish Institute of Computer Science.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  * notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  * notice, this list of conditions and the following disclaimer in the
12  * documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the Institute nor the names of its contributors
14  * may be used to endorse or promote products derived from this software
15  * without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $Id: spi.h,v 1.8 2010/06/23 10:15:28 joxe Exp $
30  */
31 
32 /**
33  * \file
34  * Basic SPI macros
35  * \author
36  * Joakim Eriksson <joakime@sics.se>
37  * Niclas Finne <nfi@sics.se>
38  */
39 
40 #ifndef __SPI_H__
41 #define __SPI_H__
42 
43 /* Define macros to use for checking SPI transmission status depending
44  on if it is possible to wait for TX buffer ready. This is possible
45  on for example MSP430 but not on AVR. */
46 #ifdef SPI_WAITFORTxREADY
47 #define SPI_WAITFORTx_BEFORE() SPI_WAITFORTxREADY()
48 #define SPI_WAITFORTx_AFTER()
49 #define SPI_WAITFORTx_ENDED() SPI_WAITFOREOTx()
50 #else /* SPI_WAITFORTxREADY */
51 #define SPI_WAITFORTx_BEFORE()
52 #define SPI_WAITFORTx_AFTER() SPI_WAITFOREOTx()
53 #define SPI_WAITFORTx_ENDED()
54 #endif /* SPI_WAITFORTxREADY */
55 
56 extern unsigned char spi_busy;
57 
58 void spi_init(void);
59 
60 /* Write one character to SPI */
61 #define SPI_WRITE(data) \
62  do { \
63  SPI_WAITFORTx_BEFORE(); \
64  SPI_TXBUF = data; \
65  SPI_WAITFOREOTx(); \
66  } while(0)
67 
68 /* Write one character to SPI - will not wait for end
69  useful for multiple writes with wait after final */
70 #define SPI_WRITE_FAST(data) \
71  do { \
72  SPI_WAITFORTx_BEFORE(); \
73  SPI_TXBUF = data; \
74  SPI_WAITFORTx_AFTER(); \
75  } while(0)
76 
77 /* Read one character from SPI */
78 #define SPI_READ(data) \
79  do { \
80  SPI_TXBUF = 0; \
81  SPI_WAITFOREORx(); \
82  data = SPI_RXBUF; \
83  } while(0)
84 
85 /* Flush the SPI read register */
86 #define SPI_FLUSH() \
87  do { \
88  SPI_RXBUF; \
89  } while(0);
90 
91 
92 #endif /* __SPI_H__ */