diff options
Diffstat (limited to 'src-avr/ao_serial.c')
| -rw-r--r-- | src-avr/ao_serial.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/src-avr/ao_serial.c b/src-avr/ao_serial.c new file mode 100644 index 00000000..9c0b798d --- /dev/null +++ b/src-avr/ao_serial.c @@ -0,0 +1,157 @@ +/* + * Copyright © 2009 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" + +volatile __xdata struct ao_fifo ao_usart1_rx_fifo; +volatile __xdata struct ao_fifo ao_usart1_tx_fifo; + +void +ao_serial_rx1_isr(void) __interrupt 3 +{ + if (!ao_fifo_full(ao_usart1_rx_fifo)) + ao_fifo_insert(ao_usart1_rx_fifo, U1DBUF); + 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, U1DBUF); + } +} + +void +ao_serial_tx1_isr(void) __interrupt 14 +{ + UTX1IF = 0; + ao_serial_tx1_started = 0; + ao_serial_tx1_start(); + ao_wakeup(&ao_usart1_tx_fifo); +} + +char +ao_serial_getchar(void) __critical +{ + char c; + while (ao_fifo_empty(ao_usart1_rx_fifo)) + ao_sleep(&ao_usart1_rx_fifo); + ao_fifo_remove(ao_usart1_rx_fifo, c); + return c; +} + +#if USE_SERIAL_STDIN +char +ao_serial_pollchar(void) __critical +{ + char c; + if (ao_fifo_empty(ao_usart1_rx_fifo)) + return AO_READ_AGAIN; + ao_fifo_remove(ao_usart1_rx_fifo,c); + return c; +} +#endif + +void +ao_serial_putchar(char c) __critical +{ + 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(); +} + +void +ao_serial_drain(void) __critical +{ + while (!ao_fifo_empty(ao_usart1_tx_fifo)) + ao_sleep(&ao_usart1_tx_fifo); +} + +static const struct { + uint8_t baud; + uint8_t gcr; +} ao_serial_speeds[] = { + /* [AO_SERIAL_SPEED_4800] = */ { + /* .baud = */ 163, + /* .gcr = */ (7 << UxGCR_BAUD_E_SHIFT) | UxGCR_ORDER_LSB + }, + /* [AO_SERIAL_SPEED_9600] = */ { + /* .baud = */ 163, + /* .gcr = */ (8 << UxGCR_BAUD_E_SHIFT) | UxGCR_ORDER_LSB + }, + /* [AO_SERIAL_SPEED_19200] = */ { + /* .baud = */ 163, + /* .gcr = */ (9 << UxGCR_BAUD_E_SHIFT) | UxGCR_ORDER_LSB + }, + /* [AO_SERIAL_SPEED_57600] = */ { + /* .baud = */ 59, + /* .gcr = */ (11 << UxGCR_BAUD_E_SHIFT) | UxGCR_ORDER_LSB + }, +}; + +void +ao_serial_set_speed(uint8_t speed) +{ + ao_serial_drain(); + if (speed > AO_SERIAL_SPEED_57600) + return; + U1UCR |= UxUCR_FLUSH; + U1BAUD = ao_serial_speeds[speed].baud; + U1GCR = ao_serial_speeds[speed].gcr; +} + +void +ao_serial_init(void) +{ + /* Set up the USART pin assignment */ + PERCFG = (PERCFG & ~PERCFG_U1CFG_ALT_MASK) | PERCFG_U1CFG_ALT_2; + + P2SEL = (P2SEL & ~(P2SEL_PRI3P1_MASK | P2SEL_PRI2P1_MASK)) | + (P2SEL_PRI3P1_USART1 | P2SEL_PRI2P1_USART1); + + /* Make the USART pins be controlled by the USART */ + P1SEL |= (1 << 6) | (1 << 7); + + /* UART mode with receiver enabled */ + U1CSR = (UxCSR_MODE_UART | UxCSR_RE); + + /* Pick a 4800 baud rate */ + ao_serial_set_speed(AO_SERIAL_SPEED_4800); + + /* Reasonable serial parameters */ + U1UCR = (UxUCR_FLUSH | + UxUCR_FLOW_DISABLE | + UxUCR_D9_EVEN_PARITY | + UxUCR_BIT9_8_BITS | + UxUCR_PARITY_DISABLE | + UxUCR_SPB_1_STOP_BIT | + UxUCR_STOP_HIGH | + UxUCR_START_LOW); + + IEN0 |= IEN0_URX1IE; + IEN2 |= IEN2_UTX1IE; +} |