Diff: mbed/drivers/SPISlave.h

Revision:

0:d6c9b09b4042

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed/drivers/SPISlave.h	Wed Dec 02 18:02:03 2020 +0000
@@ -0,0 +1,128 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef MBED_SPISLAVE_H
+#define MBED_SPISLAVE_H
+
+#include "platform/platform.h"
+
+#if DEVICE_SPISLAVE
+
+#include "hal/spi_api.h"
+
+namespace mbed {
+/** \addtogroup drivers */
+/** @{*/
+
+/** A SPI slave, used for communicating with a SPI Master device
+ *
+ * The default format is set to 8-bits, mode 0, and a clock frequency of 1MHz
+ *
+ * @Note Synchronization level: Not protected
+ *
+ * Example:
+ * @code
+ * // Reply to a SPI master as slave
+ *
+ * #include "mbed.h"
+ *
+ * SPISlave device(p5, p6, p7, p8); // mosi, miso, sclk, ssel
+ *
+ * int main() {
+ *     device.reply(0x00);              // Prime SPI with first reply
+ *     while(1) {
+ *         if(device.receive()) {
+ *             int v = device.read();   // Read byte from master
+ *             v = (v + 1) % 0x100;     // Add one to it, modulo 256
+ *             device.reply(v);         // Make this the next reply
+ *         }
+ *     }
+ * }
+ * @endcode
+ */
+class SPISlave {
+
+public:
+
+    /** Create a SPI slave connected to the specified pins
+     *
+     *  mosi or miso can be specfied as NC if not used
+     *
+     *  @param mosi SPI Master Out, Slave In pin
+     *  @param miso SPI Master In, Slave Out pin
+     *  @param sclk SPI Clock pin
+     *  @param ssel SPI chip select pin
+     */
+    SPISlave(PinName mosi, PinName miso, PinName sclk, PinName ssel);
+
+    /** Configure the data transmission format
+     *
+     *  @param bits Number of bits per SPI frame (4 - 16)
+     *  @param mode Clock polarity and phase mode (0 - 3)
+     *
+     * @code
+     * mode | POL PHA
+     * -----+--------
+     *   0  |  0   0
+     *   1  |  0   1
+     *   2  |  1   0
+     *   3  |  1   1
+     * @endcode
+     */
+    void format(int bits, int mode = 0);
+
+    /** Set the spi bus clock frequency
+     *
+     *  @param hz SCLK frequency in hz (default = 1MHz)
+     */
+    void frequency(int hz = 1000000);
+
+    /** Polls the SPI to see if data has been received
+     *
+     *  @returns
+     *    0 if no data,
+     *    1 otherwise
+     */
+    int receive(void);
+
+    /** Retrieve  data from receive buffer as slave
+     *
+     *  @returns
+     *    the data in the receive buffer
+     */
+    int read(void);
+
+    /** Fill the transmission buffer with the value to be written out
+     *  as slave on the next received message from the master.
+     *
+     *  @param value the data to be transmitted next
+     */
+    void reply(int value);
+
+protected:
+    spi_t _spi;
+
+    int _bits;
+    int _mode;
+    int _hz;
+};
+
+} // namespace mbed
+
+#endif
+
+#endif
+
+/** @}*/