+++ /dev/null
-/**
- * \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 implementation.
- *
- * \version $Id$
- * \author Luca Ottaviano <lottaviano@develer.com>
- */
-
-#include "i2s.h"
-
-#include <drv/timer.h>
-#include <cfg/log.h>
-#include <io/arm.h>
-
-#define DATALEN (15 & SSC_DATLEN_MASK)
-// FIXME: this is not correct for 16 <= DATALEN < 24
-#define PDC_DIV ((DATALEN / 8) + 1)
-/* PDC_DIV must be 1, 2 or 4, which are the bytes that are transferred
- * each time the PDC reads from memory.
- */
-STATIC_ASSERT(PDC_DIV % 2 == 0);
-#define PDC_COUNT (CONFIG_PLAY_BUF_LEN / PDC_DIV)
-
-static uint8_t play_buf1[CONFIG_PLAY_BUF_LEN];
-static uint8_t play_buf2[CONFIG_PLAY_BUF_LEN];
-
-// the buffer in PDC next is play_buf2
-volatile bool is_second_buf_next;
-
-uint8_t *i2s_getBuffer(unsigned buf_num)
-{
- LOG_INFO("getBuffer start\n");
-
- if (i2s_isPlaying())
- {
- ASSERT(0);
- return 0;
- }
-
- if (buf_num == I2S_SECOND_BUF)
- return play_buf2;
- else if (buf_num == I2S_FIRST_BUF)
- return play_buf1;
- else
- return 0;
-}
-
-uint8_t *i2s_getFreeBuffer(void)
-{
- if (!i2s_isPlaying())
- {
- ASSERT(0);
- return 0;
- }
-
- // wait PDC transmission end
- if (!(SSC_SR & BV(SSC_ENDTX)))
- return 0;
-
- uint8_t *ret_buf = 0;
- // the last time we got called, the second buffer was in PDC next
- if (is_second_buf_next)
- {
- is_second_buf_next = false;
- ret_buf = play_buf1;
- }
- // the last time the first buffer was in PDC next
- else
- {
- is_second_buf_next = true;
- ret_buf = play_buf2;
- }
-
- if (ret_buf)
- {
- SSC_TNPR = (reg32_t) ret_buf;
- SSC_TNCR = PDC_COUNT;
- }
- return ret_buf;
-}
-
-bool i2s_start(void)
-{
- /* Some time must pass between disabling and enabling again the transmission
- * on SSC. A good empirical value seems >15 us. We try to avoid putting an
- * explicit delay, instead we disable the transmitter when a sound finishes
- * and hope that the delay has passed before we enter here again.
- */
- SSC_CR = BV(SSC_TXDIS);
- timer_delay(10);
-
- SSC_PTCR = BV(PDC_TXTDIS);
- SSC_TPR = (reg32_t)play_buf1;
- SSC_TCR = PDC_COUNT;
- SSC_TNPR = (reg32_t)play_buf2;
- SSC_TNCR = PDC_COUNT;
- is_second_buf_next = true;
-
- SSC_PTCR = BV(PDC_TXTEN);
-
- /* enable output */
- SSC_CR = BV(SSC_TXEN);
-
- return true;
-}
-
-#define CONFIG_SAMPLE_FREQ 44100
-#define BITS_PER_CHANNEL 16
-#define N_OF_CHANNEL 2
-// TODO: check the computed value?
-/* The last parameter (2) is due to the hadware on at91sam7s. */
-#define MCK_DIV (CPU_FREQ / CONFIG_SAMPLE_FREQ / BITS_PER_CHANNEL / N_OF_CHANNEL / 2)
-
-#define CONFIG_DELAY 1
-#define CONFIG_PERIOD 15
-#define CONFIG_DATNB 1
-#define CONFIG_FSLEN 15
-
-#define DELAY ((CONFIG_DELAY << SSC_STTDLY_SHIFT) & SSC_STTDLY_MASK)
-#define PERIOD ((CONFIG_PERIOD << (SSC_PERIOD_SHIFT)) & SSC_PERIOD_MASK)
-#define DATNB ((CONFIG_DATNB << SSC_DATNB_SHIFT) & SSC_DATNB_MASK)
-#define FSLEN ((CONFIG_FSLEN << SSC_FSLEN_SHIFT) & SSC_FSLEN_MASK)
-
-#define SSC_DMA_IRQ_PRIORITY 5
-
-void i2s_init(void)
-{
- PIOA_PDR = BV(SSC_TK) | BV(SSC_TF) | BV(SSC_TD);
- /* reset device */
- SSC_CR = BV(SSC_SWRST);
-
- SSC_CMR = MCK_DIV & SSC_DIV_MASK;
- SSC_TCMR = SSC_CKS_DIV | SSC_CKO_CONT | SSC_CKG_NONE | DELAY | PERIOD | SSC_START_FALL_F;
- SSC_TFMR = DATALEN | DATNB | FSLEN | BV(SSC_MSBF) | SSC_FSOS_NEGATIVE;
-
- /* Disable all irqs */
- SSC_IDR = 0xFFFFFFFF;
-
- /* Enable the SSC IRQ */
- AIC_IECR = BV(SSC_ID);
-
- /* enable i2s */
- PMC_PCER = BV(SSC_ID);
-
- /* Enable SSC */
- SSC_CR = BV(SSC_TXEN);
-}
projects / bertos.git / blobdiff