/* * This file is part of the libopenstm32 project. * * Copyright (C) 2009 Uwe Hermann * * 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, either version 3 of the License, or * (at your option) any later version. * * 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, see . */ #include void clock_setup(void) { /* Select HSI as SYSCLK source. */ rcc_set_sysclk_source(SW_SYSCLKSEL_HSICLK); /* Set the PLL multiplication factor to 9. */ rcc_set_pll_multiplication_factor(PLLMUL_PLL_CLK_MUL9); /* Select HSI/2 as PLL source. */ rcc_set_pll_source(PLLSRC_HSI_CLK_DIV2); rcc_set_pllxtpre(PLLXTPRE_HSE_CLK_DIV2); /* Enable PLL oscillator and wait for it to stabilize. */ rcc_osc_on(PLL); rcc_wait_for_osc_ready(PLL); /* Select PLL as SYSCLK source. */ rcc_set_sysclk_source(SW_SYSCLKSEL_PLLCLK); } void usart_setup(void) { /* Enable clocks for GPIO port B (for GPIO_USART3_TX) and USART3. */ rcc_enable_peripheral_clock(&RCC_APB2ENR, IOPBEN); rcc_enable_peripheral_clock(&RCC_APB1ENR, USART3EN); /* Setup GPIO pin GPIO_USART3_TX/GPIO10 on GPIO port B for transmit. */ gpio_set_mode(GPIOB, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART3_TX); /* Setup UART parameters. */ usart_set_baudrate(USART3, 38400); usart_set_databits(USART3, 8); usart_set_stopbits(USART3, STOPBITS_1); usart_set_mode(USART3, MODE_TX); usart_set_parity(USART3, PARITY_NONE); usart_set_flow_control(USART3, FLOWCONTROL_NONE); /* Finally enable the USART. */ usart_enable(USART3); } void gpio_setup(void) { /* Enable GPIOC clock. */ rcc_enable_peripheral_clock(&RCC_APB2ENR, IOPCEN); /* Set GPIO12 (in GPIO port C) to 'output push-pull'. */ gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO12); } int main(void) { int i, j = 0, c = 0; clock_setup(); gpio_setup(); usart_setup(); /* Blink the LED (PC12) on the board with every transmitted byte. */ while (1) { gpio_toggle(GPIOC, GPIO12); /* LED on/off */ usart_send(USART3, c + '0'); /* Send one byte on USART3. */ c = (c == 9) ? 0 : c + 1; /* Increment c. */ if ((j++ % 80) == 0) { /* Newline after line full. */ usart_send(USART3, '\r'); usart_send(USART3, '\n'); } for (i = 0; i < 80000; i++); /* Wait (needs -O0 CFLAGS). */ } return 0; } u32 *vector_table[2] __attribute__ ((section(".vectors"))) = { (u32 *)0x20000800, /* Use 2 KB stack (0x800 bytes). */ (u32 *)main, /* Use main() as reset vector for now. */ };