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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-bringup.h"
static void
clock_init(void)
{
/* disable RC clock */
CLKSEL0 &= ~(1 << RCE);
/* Disable PLL */
PLLCSR &= ~(1 << PLLE);
/* Enable external clock */
CLKSEL0 |= (1 << EXTE);
/* wait for external clock to be ready */
while ((CLKSTA & (1 << EXTON)) == 0)
;
/* select external clock */
CLKSEL0 |= (1 << CLKS);
/* Disable the clock prescaler */
cli();
CLKPR = (1 << CLKPCE);
CLKPR = 0;
sei();
/* Set up the PLL to use the crystal */
/* Use primary system clock as PLL source */
PLLFRQ = ((0 << PINMUX) | /* Use primary clock */
(0 << PLLUSB) | /* No divide by 2 for USB */
(0 << PLLTM0) | /* Disable high speed timer */
(0x4 << PDIV0)); /* 48MHz PLL clock */
/* Set the frequency of the crystal */
#if TEENSY
PLLCSR |= (1 << PINDIV); /* For 16MHz crystal on Teensy board */
#else
PLLCSR &= ~(1 << PINDIV); /* For 8MHz crystal on TeleScience board */
#endif
/* Enable the PLL */
PLLCSR |= (1 << PLLE);
while (!(PLLCSR & (1 << PLOCK)))
;
}
void
uart_send(char c)
{
LEDPORT ^= (1 << LEDOUT);
loop_until_bit_is_set(UCSR1A, UDRE1);
UDR1 = c;
}
int
uart_put(char c, FILE *stream)
{
if (c == '\n')
uart_send('\r');
uart_send(c);
return 0;
}
int
uart_get(FILE *stream)
{
loop_until_bit_is_set(UCSR1A, RXC1);
return (int) UDR1 & 0xff;
}
void
uart_init(uint16_t baud)
{
PRR1 &= ~(1 << PRUSART1);
UBRR1L = baud;
UBRR1H = baud >> 8;
UCSR1A = 0;
UCSR1B = ((1 << RXEN1) | /* Enable receiver */
(1 << TXEN1)); /* Enable transmitter */
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 */
}
static FILE mystdout = FDEV_SETUP_STREAM(uart_put, NULL, _FDEV_SETUP_WRITE);
static FILE mystdin = FDEV_SETUP_STREAM(NULL, uart_get, _FDEV_SETUP_READ);
void ao_bringup_init(void)
{
clock_init();
uart_init(F_CPU / (16UL * 9600UL) - 1);
stdout = &mystdout;
stdin = &mystdin;
if (LEDDDR & (1 << LEDDDRPIN)) {
printf ("oops, starting all over\n");
for (;;)
;
}
LEDDDR |= (1 << LEDDDRPIN);
}
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