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/*
* Copyright © 2011 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"
__xdata struct ao_fifo ao_serial1_rx_fifo;
__xdata struct ao_fifo ao_serial1_tx_fifo;
void
ao_debug_out(char c)
{
if (c == '\n')
ao_debug_out('\r');
loop_until_bit_is_set(UCSR1A, UDRE1);
UDR1 = c;
}
ISR(USART1_RX_vect)
{
if (!ao_fifo_full(ao_serial1_rx_fifo))
ao_fifo_insert(ao_serial1_rx_fifo, UDR1);
ao_wakeup(&ao_serial1_rx_fifo);
#if USE_SERIAL_1_STDIN
ao_wakeup(&ao_stdin_ready);
#endif
}
static __xdata uint8_t ao_serial_tx1_started;
static void
ao_serial1_tx_start(void)
{
if (!ao_fifo_empty(ao_serial1_tx_fifo) &&
!ao_serial_tx1_started)
{
ao_serial_tx1_started = 1;
ao_fifo_remove(ao_serial1_tx_fifo, UDR1);
}
}
ISR(USART1_UDRE_vect)
{
ao_serial1_tx_started = 0;
ao_serial1_tx_start();
ao_wakeup(&ao_serial1_tx_fifo);
}
#if USE_SERIAL_1_STDIN
int
_ao_serial1_pollchar(void)
{
char c;
if (ao_fifo_empty(ao_serial1_rx_fifo)) {
sei();
return AO_READ_AGAIN;
}
ao_fifo_remove(ao_serial1_rx_fifo,c);
return c;
}
#endif
char
ao_serial1_getchar(void) __critical
{
char c;
ao_arch_block_interrupts();
while (ao_fifo_empty(ao_serial1_rx_fifo))
ao_sleep(&ao_serial1_rx_fifo);
ao_fifo_remove(ao_serial1_rx_fifo, c);
ao_arch_release_interrupts();
return c;
}
void
ao_serial1_putchar(char c)
{
ao_arch_block_interrupts();
while (ao_fifo_full(ao_serial1_tx_fifo))
ao_sleep(&ao_serial1_tx_fifo);
ao_fifo_insert(ao_serial1_tx_fifo, c);
ao_serial_tx1_start();
ao_arch_release_interrupts();
}
void
ao_serial1_drain(void) __critical
{
ao_arch_block_interrupts();
while (!ao_fifo_empty(ao_serial1_tx_fifo))
ao_sleep(&ao_serial1_tx_fifo);
ao_arch_release_interrupts();
}
static const struct {
uint16_t ubrr;
} ao_serial_speeds[] = {
/* [AO_SERIAL_SPEED_4800] = */ {
F_CPU / (16UL * 4800UL) - 1
},
/* [AO_SERIAL_SPEED_9600] = */ {
F_CPU / (16UL * 9600UL) - 1
},
/* [AO_SERIAL_SPEED_19200] = */ {
F_CPU / (16UL * 19200UL) - 1
},
/* [AO_SERIAL_SPEED_57600] = */ {
F_CPU / (16UL * 57600UL) - 1
},
};
void
ao_serial1_set_speed(uint8_t speed)
{
ao_serial_drain();
if (speed > AO_SERIAL_SPEED_57600)
return;
UBRR1L = ao_serial_speeds[speed].ubrr;
UBRR1H = ao_serial_speeds[speed].ubrr >> 8;
}
void
ao_serial_init(void)
{
/* Ensure the uart is powered up */
PRR1 &= ~(1 << PRUSART1);
/* Pick a 9600 baud rate */
ao_serial_set_speed(AO_SERIAL_SPEED_9600);
UCSR1A = 0;
UCSR1C = ((0 << UMSEL10) | /* Asynchronous mode */
(0 << UPM10) | /* No parity */
(0 << USBS1) | /* 1 stop bit */
(3 << UCSZ10) | /* 8 bit characters */
(0 << UCPOL1)); /* MBZ for async mode */
UCSR1B = ((1 << RXEN1) | /* Enable receiver */
(1 << TXEN1) | /* Enable transmitter */
(1 << RXCIE1) | /* Enable receive interrupts */
(1 << UDRIE1)); /* Enable transmit empty interrupts */
#if USE_SERIAL_1_STDIN
ao_add_stdio(_ao_serial1_pollchar,
ao_serial1_putchar,
NULL);
#endif
}
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