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/*
* Copyright © 2012 Keith Packard <keithp@keithp.com>
*
* 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; version 2 of the License.
*
* 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.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include <ao.h>
#include <ao_async.h>
#define AO_ASYNC_BAUD 38400l
#define AO_ASYNC_DELAY (uint8_t) (1000000l / AO_ASYNC_BAUD)
#define LED_PORT PORTB
void
ao_async_start(void)
{
LED_PORT |= (1 << AO_LED_SERIAL);
}
void
ao_async_stop(void)
{
LED_PORT &= ~(1 << AO_LED_SERIAL);
}
void
ao_async_byte(uint8_t byte)
{
uint8_t b;
uint16_t w;
/* start data stop */
w = (0x000 << 0) | (byte << 1) | (0x001 << 9);
ao_arch_block_interrupts();
for (b = 0; b < 10; b++) {
uint8_t v = LED_PORT & ~(1 << AO_LED_SERIAL);
v |= (w & 1) << AO_LED_SERIAL;
LED_PORT = v;
w >>= 1;
/* Carefully timed to hit around 9600 baud */
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
asm volatile ("nop");
}
ao_arch_release_interrupts();
}
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