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SPISlave.h
1 /* mbed Microcontroller Library
2  * Copyright (c) 2006-2013 ARM Limited
3  * SPDX-License-Identifier: Apache-2.0
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 #ifndef MBED_SPISLAVE_H
18 #define MBED_SPISLAVE_H
19 
20 #include "platform/platform.h"
21 #include "platform/NonCopyable.h"
22 
23 #if DEVICE_SPISLAVE || defined(DOXYGEN_ONLY)
24 
25 #include "hal/spi_api.h"
26 
27 namespace mbed {
28 /**
29  * \defgroup drivers_SPISlave SPISlave class
30  * \ingroup drivers-public-api-spi
31  * @{
32  */
33 
34 /** A SPI slave, used for communicating with a SPI master device.
35  *
36  * The default format is set to 8 bits, mode 0 and a clock frequency of 1MHz.
37  *
38  * @note Synchronization level: Not protected
39  *
40  * Example of how to reply to a SPI master as slave:
41  * @code
42  *
43  * #include "mbed.h"
44  *
45  * SPISlave device(SPI_MOSI, SPI_MISO, SPI_SCLK, SPI_CS);
46  *
47  * int main() {
48  * device.reply(0x00); // Prime SPI with first reply
49  * while(1) {
50  * if(device.receive()) {
51  * int v = device.read(); // Read byte from master
52  * v = (v + 1) % 0x100; // Add one to it, modulo 256
53  * device.reply(v); // Make this the next reply
54  * }
55  * }
56  * }
57  * @endcode
58  */
59 class SPISlave : private NonCopyable<SPISlave> {
60 
61 public:
62 
63  /** Create a SPI slave connected to the specified pins.
64  *
65  * @note Either mosi or miso can be specified as NC if not used.
66  *
67  * @param mosi SPI Master Out, Slave In pin.
68  * @param miso SPI Master In, Slave Out pin.
69  * @param sclk SPI Clock pin.
70  * @param ssel SPI Chip Select pin.
71  */
72  SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel);
73 
74  /** Configure the data transmission format.
75  *
76  * @param bits Number of bits per SPI frame (4 - 16).
77  * @param mode Clock polarity and phase mode (0 - 3).
78  *
79  * @code
80  * mode | POL PHA
81  * -----+--------
82  * 0 | 0 0
83  * 1 | 0 1
84  * 2 | 1 0
85  * 3 | 1 1
86  * @endcode
87  */
88  void format(int bits, int mode = 0);
89 
90  /** Set the SPI bus clock frequency.
91  *
92  * @param hz Clock frequency in hz (default = 1MHz).
93  */
94  void frequency(int hz = 1000000);
95 
96  /** Polls the SPI to see if data has been received.
97  *
98  * @return Presence of received data.
99  * @retval 0 No data waiting.
100  * @retval 1 Data waiting.
101  */
102  int receive(void);
103 
104  /** Retrieve data from receive buffer as slave.
105  *
106  * @return The data in the receive buffer.
107  */
108  int read(void);
109 
110  /** Fill the transmission buffer with the value to be written out
111  * as slave on the next received message from the master.
112  *
113  * @param value The data to be transmitted next.
114  */
115  void reply(int value);
116 
117 #if !defined(DOXYGEN_ONLY)
118 
119 protected:
120  /* Internal SPI object identifying the resources */
121  spi_t _spi;
122 
123  /* How many bits in an SPI frame */
124  int _bits;
125  /* Clock phase and polarity */
126  int _mode;
127  /* Clock frequency */
128  int _hz;
129 
130 #endif //!defined(DOXYGEN_ONLY)
131 };
132 
133 /** @}*/
134 
135 } // namespace mbed
136 
137 #endif
138 
139 #endif
mbed::SPISlave::receive
int receive(void)
Polls the SPI to see if data has been received.
mbed::SPISlave::frequency
void frequency(int hz=1000000)
Set the SPI bus clock frequency.
mbed::NonCopyable
Prevents generation of copy constructor and copy assignment operator in derived classes.
Definition: NonCopyable.h:169
mbed::SPISlave::SPISlave
SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel)
Create a SPI slave connected to the specified pins.
mbed::SPISlave::format
void format(int bits, int mode=0)
Configure the data transmission format.
mbed::SPISlave::reply
void reply(int value)
Fill the transmission buffer with the value to be written out as slave on the next received message f...
mbed::SPISlave::read
int read(void)
Retrieve data from receive buffer as slave.
mbed::SPISlave
A SPI slave, used for communicating with a SPI master device.
Definition: SPISlave.h:59
spi_t
Asynch SPI HAL structure.
Definition: spi_api.h:43
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