diff options
Diffstat (limited to 'src/lpc/ao_serial_lpc.c')
| -rw-r--r-- | src/lpc/ao_serial_lpc.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/src/lpc/ao_serial_lpc.c b/src/lpc/ao_serial_lpc.c new file mode 100644 index 00000000..431ae98a --- /dev/null +++ b/src/lpc/ao_serial_lpc.c @@ -0,0 +1,213 @@ +/* + * Copyright © 2013 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_serial.h> + +struct ao_fifo ao_usart_rx_fifo; +struct ao_fifo ao_usart_tx_fifo; +uint8_t ao_usart_tx_avail; +uint8_t ao_usart_tx_avail_min; + +#define LPC_USART_TX_FIFO_SIZE 16 + +void +ao_debug_out(char c) +{ + if (c == '\n') + ao_debug_out('\r'); + while (!(lpc_usart.lsr & (1 << LPC_USART_LSR_TEMT))) + ; + lpc_usart.rbr_thr = c; +} + +static void +_ao_serial_tx_start(void) +{ + if (!ao_fifo_empty(ao_usart_tx_fifo) && ao_usart_tx_avail) { + ao_usart_tx_avail--; + if (ao_usart_tx_avail < ao_usart_tx_avail_min) + ao_usart_tx_avail_min = ao_usart_tx_avail; + ao_fifo_remove(ao_usart_tx_fifo, lpc_usart.rbr_thr); + } +} + +void +lpc_usart_isr(void) +{ + uint8_t wake_input = 0; + (void) lpc_usart.iir_fcr; + + while (lpc_usart.lsr & (1 << LPC_USART_LSR_RDR)) { + char c = lpc_usart.rbr_thr; + if (!ao_fifo_full(ao_usart_rx_fifo)) + ao_fifo_insert(ao_usart_rx_fifo, c); + wake_input = 1; + } + if (lpc_usart.lsr & (1 << LPC_USART_LSR_THRE)) { + ao_usart_tx_avail = LPC_USART_TX_FIFO_SIZE; + _ao_serial_tx_start(); + ao_wakeup(&ao_usart_tx_fifo); + } + if (wake_input) { + ao_wakeup(&ao_usart_rx_fifo); + if (stdin) + ao_wakeup(&ao_stdin_ready); + } +} + +int +_ao_serial0_pollchar(void) +{ + int c; + + if (ao_fifo_empty(ao_usart_rx_fifo)) + c = AO_READ_AGAIN; + else { + uint8_t u; + ao_fifo_remove(ao_usart_rx_fifo,u); + c = u; + } + return c; +} + +char +ao_serial0_getchar(void) +{ + int c; + ao_arch_block_interrupts(); + while ((c = _ao_serial0_pollchar()) == AO_READ_AGAIN) + ao_sleep(&ao_usart_rx_fifo); + ao_arch_release_interrupts(); + return (char) c; +} + +void +ao_serial0_putchar(char c) +{ + ao_arch_block_interrupts(); + while (ao_fifo_full(ao_usart_tx_fifo)) + ao_sleep(&ao_usart_tx_fifo); + ao_fifo_insert(ao_usart_tx_fifo, c); + _ao_serial_tx_start(); + ao_arch_release_interrupts(); +} + +void +ao_serial0_drain(void) +{ + ao_arch_block_interrupts(); + while (!ao_fifo_empty(ao_usart_tx_fifo)) + ao_sleep(&ao_usart_tx_fifo); + ao_arch_release_interrupts(); +} + +#include "ao_serial_lpc.h" + +void +ao_serial0_set_speed(uint8_t speed) +{ + if (speed > AO_SERIAL_SPEED_115200) + return; + + /* Flip to allow access to divisor latches */ + lpc_usart.lcr |= (1 << LPC_USART_LCR_DLAB); + + /* DL LSB */ + lpc_usart.rbr_thr = ao_usart_speeds[speed].dl & 0xff; + + /* DL MSB */ + lpc_usart.ier = (ao_usart_speeds[speed].dl >> 8) & 0xff; + + lpc_usart.fdr = ((ao_usart_speeds[speed].divaddval << LPC_USART_FDR_DIVADDVAL) | + (ao_usart_speeds[speed].mulval << LPC_USART_FDR_MULVAL)); + + /* Turn access to divisor latches back off */ + lpc_usart.lcr &= ~(1 << LPC_USART_LCR_DLAB); +} + +void +ao_serial_init(void) +{ +#if SERIAL_0_18_19 + lpc_ioconf.pio0_18 = ((LPC_IOCONF_FUNC_PIO0_18_RXD << LPC_IOCONF_FUNC) | + (LPC_IOCONF_MODE_INACTIVE << LPC_IOCONF_MODE) | + (0 << LPC_IOCONF_HYS) | + (0 << LPC_IOCONF_INV) | + (0 << LPC_IOCONF_OD)); + lpc_ioconf.pio0_19 = ((LPC_IOCONF_FUNC_PIO0_19_TXD << LPC_IOCONF_FUNC) | + (LPC_IOCONF_MODE_INACTIVE << LPC_IOCONF_MODE) | + (0 << LPC_IOCONF_HYS) | + (0 << LPC_IOCONF_INV) | + (0 << LPC_IOCONF_OD)); +#endif + + /* Turn on the USART */ + lpc_scb.sysahbclkctrl |= (1 << LPC_SCB_SYSAHBCLKCTRL_USART); + + /* Turn on the USART clock */ + lpc_scb.uartclkdiv = AO_LPC_CLKOUT / AO_LPC_USARTCLK; + + /* Configure USART */ + + /* Enable FIFOs, reset fifo contents, interrupt on 1 received char */ + lpc_usart.iir_fcr = ((1 << LPC_USART_FCR_FIFOEN) | + (1 << LPC_USART_FCR_RXFIFORES) | + (1 << LPC_USART_FCR_TXFIFORES) | + (LPC_USART_FCR_RXTL_1 << LPC_USART_FCR_RXTL)); + + ao_usart_tx_avail = LPC_USART_TX_FIFO_SIZE; + ao_usart_tx_avail_min = LPC_USART_TX_FIFO_SIZE; + + /* 8 n 1 */ + lpc_usart.lcr = ((LPC_USART_LCR_WLS_8 << LPC_USART_LCR_WLS) | + (LPC_USART_LCR_SBS_1 << LPC_USART_LCR_SBS) | + (0 << LPC_USART_LCR_PE) | + (LPC_USART_LCR_PS_ODD << LPC_USART_LCR_PS) | + (0 << LPC_USART_LCR_BC) | + (0 << LPC_USART_LCR_DLAB)); + + /* Disable flow control */ + lpc_usart.mcr = ((0 << LPC_USART_MCR_DTRCTRL) | + (0 << LPC_USART_MCR_RTSCTRL) | + (0 << LPC_USART_MCR_LMS) | + (0 << LPC_USART_MCR_RTSEN) | + (0 << LPC_USART_MCR_CTSEN)); + + /* 16x oversampling */ + lpc_usart.osr = ((0 << LPC_USART_OSR_OSFRAC) | + ((16 - 1) << LPC_USART_OSR_OSINT) | + (0 << LPC_USART_OSR_FDINT)); + + /* Full duplex */ + lpc_usart.hden = ((0 << LPC_USART_HDEN_HDEN)); + + /* Set baud rate */ + ao_serial0_set_speed(AO_SERIAL_SPEED_9600); + + /* Enable interrupts */ + lpc_usart.ier = ((1 << LPC_USART_IER_RBRINTEN) | + (1 << LPC_USART_IER_THREINTEN)); + + lpc_nvic_set_enable(LPC_ISR_USART_POS); + lpc_nvic_set_priority(LPC_ISR_USART_POS, 0); +#if USE_SERIAL_0_STDIN + ao_add_stdio(_ao_serial_pollchar, + ao_serial_putchar, + NULL); +#endif +} |