+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction. Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License. This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2009 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ *
+ * \brief I2S driver functions.
+ *
+ * This driver uses a double buffering technique to keep i2s bus busy. First fill in the two buffers
+ * using i2s_getBuffer(), then start audio playing with i2s_start(). Then call i2s_getFreeBuffer()
+ * until you have finished your samples. The reproduction will automatically stop if you don't
+ * call i2s_getFreeBuffer() frequently enough.
+ *
+ * Example:
+ * \code
+ * // fill in the buffers before start
+ * buf = i2s_getBuffer(I2S_FIRST_BUF);
+ * // ...
+ * buf = i2s_getBuffer(I2S_SECOND_BUF);
+ * // ...
+ * // here the driver will play only the first two buffers...
+ * i2s_start();
+ * // ...call getFreeBuffer() to continue playing.
+ * while (!(buf = i2s_getFreeBuffer()))
+ * ;
+ * // now fill the buffer again
+ * \endcode
+ *
+ * \version $Id$
+ * \author Luca Ottaviano <lottaviano@develer.com>
+ *
+ * $WIZ$ module_name = "i2s"
+ * $WIZ$ module_configuration = "bertos/cfg/cfg_i2s.h"
+ * $WIZ$ module_supports = "not atmega103 and not atmega168 and not atmega8"
+ */
+
#ifndef I2S_H
#define I2S_H
+#include "cfg/cfg_i2s.h"
+
#include <cfg/compiler.h>
+#include <cfg/macros.h>
+#include <io/arm.h>
-#define CONFIG_PLAY_BUF_LEN 64
-#define I2S_FIRST_BUF 1
-#define I2S_SECOND_BUF 2
+/**
+ * First buffer.
+ */
+#define I2S_FIRST_BUF 0
+/**
+ * Second buffer.
+ */
+#define I2S_SECOND_BUF 1
+/**
+ * Initializes the module and sets current buffer to I2S_FIRST_BUF.
+ */
void i2s_init(void);
-/* Low level call that returns one of the two buffers or NULL if none is available */
+/**
+ * Returns one of the two buffers or NULL if none is available.
+ *
+ * You can't call this function if you have already started the player.
+ * \param buf_num The number of the buffer, ie I2S_FIRST_BUF or I2S_SECOND_BUF.
+ * \return A pointer to the buffer if the buffer is available (not full), 0 on errors
+ */
uint8_t *i2s_getBuffer(unsigned buf_num);
-/* Returns a buffer that will be played after the current one. Blocking call */
+/**
+ * Returns a buffer that will be played after the current one.
+ *
+ * You should fill it faster than your reproduction time. You can't call this function
+ * if the player is not running
+ * \return The next buffer to be played, 0 if both are busy.
+ */
uint8_t *i2s_getFreeBuffer(void);
-/* Starts playing from I2S_FIRST_BUFFER. You must have filled both buffers before calling this
- * function. Does nothing if already playing. */
+/**
+ * Starts playing from I2S_FIRST_BUFFER.
+ *
+ * You must have filled both buffers before calling this function. Does nothing if already playing.
+ * \return false on errors, true otherwise.
+ */
bool i2s_start(void);
+INLINE bool i2s_isPlaying(void)
+{
+ return !(SSC_SR & BV(SSC_TXEMPTY));
+}
+
#endif /* I2S_H */
projects / bertos.git / blobdiff