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Diffstat (limited to 'src/stm/ao_serial_stm.c')
| -rw-r--r-- | src/stm/ao_serial_stm.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/src/stm/ao_serial_stm.c b/src/stm/ao_serial_stm.c new file mode 100644 index 00000000..dc446120 --- /dev/null +++ b/src/stm/ao_serial_stm.c @@ -0,0 +1,184 @@ +/* + * Copyright © 2012 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'); + while (!(STM_USART1->usart_sr & (1 << STM_USART_SR_TXE))); + STM_USART1->usart_dr = c; +} + +#if 0 +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, STM_USART1->usart_dr); + } +} + +void usart1_isr(void) +{ + if (STM_USART1->usart_sr & (1 << STM_USART_SR_RXNE)) { + if (!ao_fifo_full(ao_usart1_rx_fifo)) + ao_fifo_insert(ao_usart1_rx_fifo, STM_USART1->usart_dr); + ao_wakeup(&ao_usart1_rx_fifo); +#if USE_SERIAL_STDIN + ao_wakeup(&ao_stdin_ready); +#endif + } + if (STM_USART1->usart_sr & (1 << STM_USART_SR_TXE)) { + 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(); +} + +#endif + +int _write(int file, char *ptr, int len) +{ + int l = len; + while (l--) + ao_debug_out(*ptr++); + return len; +} + +#define F_CPU 24000000 + +static const struct { + uint32_t usart_brr; +} ao_serial_speeds[] = { + [AO_SERIAL_SPEED_4800] = { + (F_CPU * 16) / (16 * 4800) + }, + [AO_SERIAL_SPEED_9600] = { + (F_CPU * 16) / (16 * 9600) + }, + [AO_SERIAL_SPEED_19200] = { + (F_CPU * 16) / (16 * 19200) + }, + [AO_SERIAL_SPEED_57600] = { + (F_CPU * 16) / (16 * 57600) + }, +}; + +void +ao_serial_set_speed(uint8_t speed) +{ +#if 0 + ao_serial_drain(); +#endif + if (speed > AO_SERIAL_SPEED_57600) + return; + STM_USART1->usart_brr = ao_serial_speeds[speed].usart_brr; +} + +void +ao_serial_init(void) +{ + STM_USART1->usart_cr1 = ((0 << STM_USART_CR1_OVER8) | + (1 << STM_USART_CR1_UE) | + (0 << STM_USART_CR1_M) | + (0 << STM_USART_CR1_WAKE) | + (0 << STM_USART_CR1_PCE) | + (0 << STM_USART_CR1_PS) | + (0 << STM_USART_CR1_PEIE) | + (0 << STM_USART_CR1_TXEIE) | /* XXX enable */ + (0 << STM_USART_CR1_TCIE) | + (0 << STM_USART_CR1_RXNEIE) | /* XXX enable */ + (0 << STM_USART_CR1_IDLEIE) | + (1 << STM_USART_CR1_TE) | + (1 << STM_USART_CR1_RE) | + (0 << STM_USART_CR1_RWU) | + (0 << STM_USART_CR1_SBK)); + + STM_USART1->usart_cr2 = 0; + STM_USART1->usart_cr3 = 0; + + /* Pick a 9600 baud rate */ + ao_serial_set_speed(AO_SERIAL_SPEED_9600); + + printf ("serial initialized\n"); +#if 0 +#if USE_SERIAL_STDIN + ao_add_stdio(ao_serial_pollchar, + ao_serial_putchar, + NULL); +#endif +#endif +} |