rockbox/firmware/target/arm/as3525/dbop-as3525.c
Tobias Diedrich eefe273ce6 DBOP noise on C200v2 goes away if we precharge long enough.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@27148 a1c6a512-1295-4272-9138-f99709370657
2010-06-27 02:50:24 +00:00

144 lines
4.7 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2009 by Bertrik Sikken
*
* This program 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include <inttypes.h>
#include "as3525.h"
#include "dbop-as3525.h"
#if defined(SANSA_FUZE) || defined(SANSA_FUZEV2)
#define DBOP_PRECHARGE 0x80FF
#elif defined(SANSA_E200V2) || defined(SANSA_C200V2)
#define DBOP_PRECHARGE 0xF0FF
#endif
#if CONFIG_CPU == AS3525
/* doesn't work with the new ams sansas so far and is not needed */
static short int dbop_input_value = 0;
/* read the DBOP data pins */
unsigned short dbop_read_input(void)
{
unsigned int dbop_ctrl_old = DBOP_CTRL;
unsigned int dbop_timpol23_old = DBOP_TIMPOL_23;
/* make sure that the DBOP FIFO is empty */
while ((DBOP_STAT & (1<<10)) == 0);
int delay = 10;
while (delay--) asm volatile ("nop\n");
/* write DBOP_DOUT to pre-charge DBOP data lines with a defined level */
DBOP_TIMPOL_23 = 0xe007e007; /* no strobe towards lcd */
DBOP_CTRL = (1 << 19) | /* tri-state output */
(1 << 16) | /* enw=1 (enable write) */
(1 << 12); /* ow=1 (16-bit data width) */
DBOP_DOUT = DBOP_PRECHARGE;
#if defined(SANSA_C200V2)
/* two additional writes to precharge longer get rid of the read noise */
DBOP_DOUT = DBOP_PRECHARGE;
DBOP_DOUT = DBOP_PRECHARGE;
#endif
while ((DBOP_STAT & (1<<10)) == 0);
#if defined(SANSA_FUZE) || defined(SANSA_E200V2)
delay = 50;
while (delay--) asm volatile ("nop\n");
#endif
/* perform a DBOP read */
DBOP_CTRL = (1 << 19) | /* tri-state output */
(1 << 15) | /* strd=1 (start read) */
(1 << 12) | /* ow=1 (16-bit data width) */
(31 << 0); /* rs_t=31 (read DBOP at end of cycle) */
while ((DBOP_STAT & (1<<16)) == 0);
dbop_input_value = DBOP_DIN;
/* restore previous values */
DBOP_TIMPOL_23 = dbop_timpol23_old;
DBOP_CTRL = dbop_ctrl_old;
return dbop_input_value;
}
/* for the debug menu */
unsigned short dbop_debug(void)
{
return dbop_input_value;
}
#endif
static inline void dbop_set_mode(int mode)
{
int delay = 10;
unsigned long ctrl = DBOP_CTRL;
int curr_mode = (DBOP_CTRL >> 13) & 0x3; // bits 14:13
#ifdef SANSA_FUZEV2
if (mode == 32 && curr_mode != 1<<1)
DBOP_CTRL = (ctrl & ~(1<<13)) | (1<<14); // 2 serial half words
else if (mode == 16 && curr_mode != 1<<0)
DBOP_CTRL = (ctrl & ~(1<<14)) | (1<<13); // 2 serial bytes
#else
if (mode == 32 && curr_mode == 0)
DBOP_CTRL = ctrl | (1<<13|1<<14); /* 2 serial half words */
else if (mode == 16 && curr_mode == (1<<1|1<<0))
DBOP_CTRL = ctrl & ~(1<<14|1<<13); /* 1 serial half word */
#endif
else
return;
while(delay--) asm volatile("nop");
}
void dbop_write_data(const int16_t* p_bytes, int count)
{
const int32_t *data;
if ((intptr_t)p_bytes & 0x3 || count == 1)
{ /* need to do a single 16bit write beforehand if the address is
* not word aligned or count is 1, switch to 16bit mode if needed */
dbop_set_mode(16);
DBOP_DOUT16 = *p_bytes++;
if (!(--count))
return;
}
/* from here, 32bit transfers are save
* set it to transfer 4*(outputwidth) units at a time,
* if bit 12 is set it only does 2 halfwords though (we never set it)
* switch to 32bit output if needed */
dbop_set_mode(32);
data = (int32_t*)p_bytes;
while (count > 1)
{
DBOP_DOUT32 = *data++;
count -= 2;
/* Wait if push fifo is full */
while ((DBOP_STAT & (1<<6)) != 0);
}
/* While push fifo is not empty */
while ((DBOP_STAT & (1<<10)) == 0);
/* due to the 32bit alignment requirement or uneven count,
* we possibly need to do a 16bit transfer at the end also */
if (count > 0)
dbop_write_data((int16_t*)data, 1);
}