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Diffstat (limited to 'src/avr/ao_serial_avr.c')
| -rw-r--r-- | src/avr/ao_serial_avr.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/src/avr/ao_serial_avr.c b/src/avr/ao_serial_avr.c new file mode 100644 index 00000000..2fe39755 --- /dev/null +++ b/src/avr/ao_serial_avr.c @@ -0,0 +1,166 @@ +/* + * 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_usart1_rx_fifo; +__xdata struct ao_fifo ao_usart1_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_usart1_rx_fifo)) + ao_fifo_insert(ao_usart1_rx_fifo, UDR1); + ao_wakeup(&ao_usart1_rx_fifo); +#if USE_SERIAL_STDIN + ao_wakeup(&ao_stdin_ready); +#endif +} + +static __xdata uint8_t ao_serial_tx1_started; + +static void +ao_serial_tx1_start(void) +{ + if (!ao_fifo_empty(ao_usart1_tx_fifo) && + !ao_serial_tx1_started) + { + ao_serial_tx1_started = 1; + ao_fifo_remove(ao_usart1_tx_fifo, UDR1); + } +} + +ISR(USART1_UDRE_vect) +{ + ao_serial_tx1_started = 0; + ao_serial_tx1_start(); + ao_wakeup(&ao_usart1_tx_fifo); +} + +char +ao_serial_getchar(void) __critical +{ + char c; + cli(); + while (ao_fifo_empty(ao_usart1_rx_fifo)) + ao_sleep(&ao_usart1_rx_fifo); + ao_fifo_remove(ao_usart1_rx_fifo, c); + sei(); + return c; +} + +#if USE_SERIAL_STDIN +char +ao_serial_pollchar(void) __critical +{ + char c; + cli(); + if (ao_fifo_empty(ao_usart1_rx_fifo)) { + sei(); + return AO_READ_AGAIN; + } + ao_fifo_remove(ao_usart1_rx_fifo,c); + sei(); + return c; +} +#endif + +void +ao_serial_putchar(char c) __critical +{ + cli(); + while (ao_fifo_full(ao_usart1_tx_fifo)) + ao_sleep(&ao_usart1_tx_fifo); + ao_fifo_insert(ao_usart1_tx_fifo, c); + ao_serial_tx1_start(); + sei(); +} + +void +ao_serial_drain(void) __critical +{ + cli(); + while (!ao_fifo_empty(ao_usart1_tx_fifo)) + ao_sleep(&ao_usart1_tx_fifo); + sei(); +} + +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_serial_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 0 +#if USE_SERIAL_STDIN + int8_t i; + i = ao_add_stdio(ao_serial_pollchar, + ao_serial_putchar, + NULL); + printf("Register serial stdio as %d\n", i); +#endif +#endif +} |