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fifo.c
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/
fifo.c
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/************************************************************************/
/* XBoot Extensible AVR Bootloader */
/* */
/* FT245/2232 asynchronous Fifo Module */
/* */
/* fifo.c */
/* */
/* Uwe Bonnes bon@elektron.ikp.physik.tu-darmstadt.de */
/* */
/* Copyright (c) 2011 Uwe Bonnes */
/* */
/* Permission is hereby granted, free of charge, to any person */
/* obtaining a copy of this software and associated documentation */
/* files(the "Software"), to deal in the Software without restriction, */
/* including without limitation the rights to use, copy, modify, merge, */
/* publish, distribute, sublicense, and/or sell copies of the Software, */
/* and to permit persons to whom the Software is furnished to do so, */
/* subject to the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND */
/* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS */
/* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN */
/* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN */
/* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE */
/* SOFTWARE. */
/* */
/************************************************************************/
#include "fifo.h"
/* As discussed in
* http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=41613
* Accessing a bitrev table in bootloader flash will not be faster, as
* a our character needs to be added to the table converted to a far address
* and probaly also the NVM needs to be cared about
*/
#define REVERSE(a) do \
{ \
a=((a>>1)&0x55)|((a<<1)&0xaa); \
a=((a>>2)&0x33)|((a<<2)&0xcc); \
asm volatile("swap %0":"=r"(a):"0"(a)); \
} while(0)
// Initialize FIFO
void fifo_init(void)
{
#ifdef __AVR_XMEGA__
FIFO_DATA_PORT.DIR = 0;
FIFO_CTL_PORT.OUTSET = _BV(FIFO_RD_N) | _BV(FIFO_WR_N);
FIFO_CTL_PORT.DIRSET = _BV(FIFO_RD_N) | _BV(FIFO_WR_N);
#else // __AVR_XMEGA__
FIFO_DATA_PORT_DDR = 0;
FIFO_DATA_PORT |= (_BV(FIFO_RD_N) | _BV(FIFO_WR_N));
FIFO_CTL_PORT_DDR |= (_BV(FIFO_RD_N) | _BV(FIFO_WR_N));
#endif // __AVR_XMEGA__
}
// Shut down FIFO
void fifo_deinit(void)
{
#ifdef __AVR_XMEGA__
FIFO_DATA_PORT.DIR = 0xff;
FIFO_DATA_PORT.OUTCLR = 0xff;
FIFO_CTL_PORT.OUTCLR = _BV(FIFO_RD_N) | _BV(FIFO_WR_N);
FIFO_CTL_PORT.DIRCLR = _BV(FIFO_RD_N) | _BV(FIFO_WR_N);
#else // __AVR_XMEGA__
FIFO_DATA_PORT_DDR = 0xff;
FIFO_DATA_PORT= 0x00;
FIFO_DATA_PORT &= ~(_BV(FIFO_RD_N) | _BV(FIFO_WR_N));
FIFO_CTL_PORT_DDR &= ~(_BV(FIFO_RD_N) | _BV(FIFO_WR_N));
#endif // __AVR_XMEGA__
}
uint8_t fifo_cur_char(void)
{
uint8_t ret;
#ifdef __AVR_XMEGA__
FIFO_CTL_PORT.OUTCLR = _BV(FIFO_RD_N);
ret = FIFO_DATA_PORT.IN;
#ifdef FIFO_BIT_REVERSE
REVERSE(ret);
#endif
FIFO_CTL_PORT.OUTSET = _BV(FIFO_RD_N);
#else // __AVR_XMEGA__
FIFO_CTL_PORT &= ~_BV(FIFO_RD_N);
ret = FIFO_DATA_PORT_PIN;
#ifdef FIFO_BIT_REVERSE
REVERSE(ret);
#endif
FIFO_CTL_PORT |= _BV(FIFO_RD_N);
#endif // __AVR_XMEGA__
return ret;
}
void fifo_send_char(uint8_t c)
{
#ifdef __AVR_XMEGA__
if ((FIFO_CTL_PORT.IN & _BV(FIFO_TXE_N)) != _BV(FIFO_TXE_N))
{
FIFO_DATA_PORT.DIR = 0xff;
#ifdef FIFO_BIT_REVERSE
REVERSE(c);
#endif
FIFO_DATA_PORT.OUT = c;
FIFO_DATA_PORT.DIR = 0xff;
FIFO_CTL_PORT.OUTCLR = _BV(FIFO_WR_N);
asm volatile("nop");
asm volatile("nop");
FIFO_CTL_PORT.OUTSET = _BV(FIFO_WR_N);
FIFO_DATA_PORT.DIR = 0;
}
#else // __AVR_XMEGA__
if ((FIFO_CTL_PORT_PIN & _BV(FIFO_TXE_N)) != _BV(FIFO_TXE_N))
{
FIFO_DATA_PORT_DDR = 0xff;
#ifdef FIFO_BIT_REVERSE
REVERSE(c);
#endif
FIFO_DATA_PORT = c;
FIFO_DATA_PORT_DDR = 0xff;
FIFO_CTL_PORT &= ~_BV(FIFO_WR_N);
asm volatile("nop");
asm volatile("nop");
FIFO_CTL_PORT |= _BV(FIFO_WR_N);
FIFO_DATA_PORT_DDR = 0;
}
#endif // __AVR_XMEGA__
}
void fifo_send_char_blocking(uint8_t c)
{
#ifdef __AVR_XMEGA__
while (FIFO_CTL_PORT.IN & _BV(FIFO_TXE_N))
#else // __AVR_XMEGA__
while (FIFO_CTL_PORT_PIN & _BV(FIFO_TXE_N))
#endif // __AVR_XMEGA__
{
};
fifo_send_char(c);
}