/* * This file is part of the libopencm3 project. * * Copyright (C) 2010 Lord James * * This library is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This library 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this library. If not, see . */ #include #include #include #include #include #include void clock_setup(void) { rcc_clock_setup_in_hse_8mhz_out_72mhz(); /* Enable GPIOC clock. */ rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPCEN); /* Enable clocks for GPIO port A (for GPIO_USART1_TX) and USART1. */ rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN); rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_USART1EN); } void usart_setup(void) { /* Setup GPIO pin GPIO_USART1_TX/GPIO9 on GPIO port A for transmit. */ gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX); /* Setup UART parameters. */ usart_set_baudrate(USART1, 38400); usart_set_databits(USART1, 8); usart_set_stopbits(USART1, USART_STOPBITS_1); usart_set_mode(USART1, USART_MODE_TX); usart_set_parity(USART1, USART_PARITY_NONE); usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE); /* Finally enable the USART. */ usart_enable(USART1); } void gpio_setup(void) { /* Set GPIO12 (in GPIO port C) to 'output push-pull'. */ gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO12); } void nvic_setup(void) { /* Without this the RTC interrupt routine will never be called. */ nvic_enable_irq(NVIC_RTC_IRQ); nvic_set_priority(NVIC_RTC_IRQ, 1); } void rtc_isr(void) { volatile u32 j = 0, c = 0; /* The interrupt flag isn't cleared by hardware, we have to do it. */ rtc_clear_flag(RTC_SEC); /* Visual output. */ gpio_toggle(GPIOC, GPIO12); c = rtc_get_counter_val(); /* Display the current counter value in binary via USART1. */ for (j = 0; j < 32; j++) { if ((c & (0x80000000 >> j)) != 0) { usart_send(USART1, '1'); } else { usart_send(USART1, '0'); } } usart_send(USART1, '\n'); } int main(void) { clock_setup(); gpio_setup(); usart_setup(); /* * If the RTC is pre-configured just allow access, don't reconfigure. * Otherwise enable it with the LSE as clock source and 0x7fff as * prescale value. */ rtc_auto_awake(LSE, 0x7fff); /* Setup the RTC interrupt. */ nvic_setup(); /* Enable the RTC interrupt to occur off the SEC flag. */ rtc_interrupt_enable(RTC_SEC); while (1); return 0; }