130 lines
3.7 KiB
C
130 lines
3.7 KiB
C
/*
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* This file is part of the libopencm3 project.
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*
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* Copyright (C) 2010 Lord James <lordjames@y7mail.com>
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* Copyright (C) 2011 Mark Panajotovic <marko@electrontube.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <libopencm3/stm32/f1/rcc.h>
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#include <libopencm3/stm32/f1/gpio.h>
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#include <libopencm3/stm32/f1/rtc.h>
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#include <libopencm3/stm32/usart.h>
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#include <libopencm3/stm32/pwr.h>
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#include <libopencm3/stm32/nvic.h>
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void clock_setup(void)
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{
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rcc_clock_setup_in_hse_8mhz_out_24mhz();
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/* Enable GPIOC clock. */
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPCEN);
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/* Enable clocks for GPIO port A (for GPIO_USART1_TX) and USART1. */
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN);
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rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_USART1EN);
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}
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void usart_setup(void)
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{
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/* Setup GPIO pin GPIO_USART1_TX/GPIO9 on GPIO port A for transmit. */
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gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ,
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GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX);
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/* Setup UART parameters. */
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// usart_set_baudrate(USART1, 38400);
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/* TODO usart_set_baudrate() doesn't support 24MHz clock (yet). */
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/* This is the equivalent: */
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USART_BRR(USART1) = (u16)((24000000 << 4) / (38400 * 16));
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usart_set_databits(USART1, 8);
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usart_set_stopbits(USART1, USART_STOPBITS_1);
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usart_set_mode(USART1, USART_MODE_TX);
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usart_set_parity(USART1, USART_PARITY_NONE);
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usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
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/* Finally enable the USART. */
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usart_enable(USART1);
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}
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void gpio_setup(void)
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{
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/* Set GPIO8 (in GPIO port C) to 'output push-pull'. */
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/* This drives the blue LED on the STM32VLDISCOVERY. */
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gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ,
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GPIO_CNF_OUTPUT_PUSHPULL, GPIO8);
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}
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void nvic_setup(void)
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{
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/* Without this the RTC interrupt routine will never be called. */
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nvic_enable_irq(NVIC_RTC_IRQ);
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nvic_set_priority(NVIC_RTC_IRQ, 1);
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}
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void rtc_isr(void)
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{
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volatile u32 j = 0, c = 0;
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/* The interrupt flag isn't cleared by hardware, we have to do it. */
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rtc_clear_flag(RTC_SEC);
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/* Visual output. */
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gpio_toggle(GPIOC, GPIO8);
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c = rtc_get_counter_val();
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/* Display the current counter value in binary via USART1. */
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for (j = 0; j < 32; j++) {
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if ((c & (0x80000000 >> j)) != 0)
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usart_send_blocking(USART1, '1');
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else
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usart_send_blocking(USART1, '0');
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}
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usart_send_blocking(USART1, '\n');
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usart_send_blocking(USART1, '\r');
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}
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int main(void)
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{
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clock_setup();
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gpio_setup();
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usart_setup();
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/*
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* If the RTC is pre-configured just allow access, don't reconfigure.
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* Otherwise enable it with the LSE as clock source and 0x7fff as
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* prescale value.
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*/
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rtc_auto_awake(LSE, 0x7fff);
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/* The above mode will not reset the RTC when you press the RST button.
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* It will also continue to count while the MCU is held in reset. If
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* you want it to reset, comment out the above and use the following:
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*/
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// rtc_awake_from_off(LSE);
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// rtc_set_prescale_val(0x7fff);
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/* Setup the RTC interrupt. */
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nvic_setup();
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/* Enable the RTC interrupt to occur off the SEC flag. */
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rtc_interrupt_enable(RTC_SEC);
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while(1);
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return 0;
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}
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