/* * This file is part of the libopencm3 project. * * Copyright (C) 2009 Uwe Hermann , * Copyright (C) 2011 Piotr Esden-Tempski * * 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 #include /****************************************************************************** * Simple ringbuffer implementation from open-bldc's libgovernor that * you can find at: * https://github.com/open-bldc/open-bldc/tree/master/source/libgovernor *****************************************************************************/ typedef s32 ring_size_t; struct ring { u8 *data; ring_size_t size; u32 begin; u32 end; }; #define RING_SIZE(RING) ((RING)->size - 1) #define RING_DATA(RING) (RING)->data #define RING_EMPTY(RING) ((RING)->begin == (RING)->end) void ring_init(struct ring *ring, u8 *buf, ring_size_t size) { ring->data = buf; ring->size = size; ring->begin = 0; ring->end = 0; } s32 ring_write_ch(struct ring *ring, u8 ch) { if (((ring->end + 1) % ring->size) != ring->begin) { ring->data[ring->end++] = ch; ring->end %= ring->size; return (u32)ch; } return -1; } s32 ring_write(struct ring *ring, u8 *data, ring_size_t size) { s32 i; for (i = 0; i < size; i++) { if (ring_write_ch(ring, data[i]) < 0) return -i; } return i; } s32 ring_read_ch(struct ring *ring, u8 *ch) { s32 ret = -1; if (ring->begin != ring->end) { ret = ring->data[ring->begin++]; ring->begin %= ring->size; if (ch) *ch = ret; } return ret; } s32 ring_read(struct ring *ring, u8 *data, ring_size_t size) { s32 i; for (i = 0; i < size; i++) { if (ring_read_ch(ring, data + i) < 0) return i; } return -i; } /****************************************************************************** * The example implementation *****************************************************************************/ #define BUFFER_SIZE 1024 struct ring output_ring; u8 output_ring_buffer[BUFFER_SIZE]; void clock_setup(void) { rcc_clock_setup_in_hse_12mhz_out_72mhz(); /* Enable GPIOA clock (for LED GPIOs). */ rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN); /* Enable clocks for GPIO port A (for GPIO_USART2_TX) and USART2. */ rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN | RCC_APB2ENR_AFIOEN); rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_USART2EN); } void usart_setup(void) { /* Initialize output ring buffer. */ ring_init(&output_ring, output_ring_buffer, BUFFER_SIZE); /* Enable the USART2 interrupt. */ nvic_enable_irq(NVIC_USART2_IRQ); /* Setup GPIO pin GPIO_USART2_TX on GPIO port A for transmit. */ gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART2_TX); /* Setup GPIO pin GPIO_USART2_RX on GPIO port A for receive. */ gpio_set_mode(GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO_USART2_RX); /* Setup UART parameters. */ usart_set_baudrate(USART2, 230400); usart_set_databits(USART2, 8); usart_set_stopbits(USART2, USART_STOPBITS_1); usart_set_parity(USART2, USART_PARITY_NONE); usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE); usart_set_mode(USART2, USART_MODE_TX_RX); /* Enable USART2 Receive interrupt. */ USART_CR1(USART2) |= USART_CR1_RXNEIE; /* Finally enable the USART. */ usart_enable(USART2); } void gpio_setup(void) { gpio_set(GPIOA, GPIO8); /* Setup GPIO8 (in GPIO port A) for LED use. */ gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO8); } void usart2_isr(void) { /* Check if we were called because of RXNE. */ if (((USART_CR1(USART2) & USART_CR1_RXNEIE) != 0) && ((USART_SR(USART2) & USART_SR_RXNE) != 0)) { /* Indicate that we got data. */ gpio_toggle(GPIOA, GPIO8); /* Retrieve the data from the peripheral. */ ring_write_ch(&output_ring, usart_recv(USART2)); /* Enable transmit interrupt so it sends back the data. */ USART_CR1(USART2) |= USART_CR1_TXEIE; } /* Check if we were called because of TXE. */ if (((USART_CR1(USART2) & USART_CR1_TXEIE) != 0) && ((USART_SR(USART2) & USART_SR_TXE) != 0)) { s32 data; data = ring_read_ch(&output_ring, NULL); if (data == -1) { /* Disable the TXE interrupt, it's no longer needed. */ USART_CR1(USART2) &= ~USART_CR1_TXEIE; } else { /* Put data into the transmit register. */ usart_send(USART2, data); } } } int _write(int file, char *ptr, int len) { int ret; if (file == 1) { ret = ring_write(&output_ring, (u8 *)ptr, len); if (ret < 0) ret = -ret; USART_CR1(USART2) |= USART_CR1_TXEIE; return ret; } errno = EIO; return -1; } void systick_setup(void) { /* 72MHz / 8 => 9000000 counts per second. */ systick_set_clocksource(STK_CTRL_CLKSOURCE_AHB_DIV8); /* 9000000/9000 = 1000 overflows per second - every 1ms one interrupt */ systick_set_reload(9000); systick_interrupt_enable(); /* Start counting. */ systick_counter_enable(); } void sys_tick_handler(void) { static int counter = 0; static float fcounter = 0.0; static double dcounter = 0.0; static u32 temp32 = 0; temp32++; /* * We call this handler every 1ms so we are sending hello world * every 10ms / 100Hz. */ if (temp32 == 10) { printf("Hello World! %i %f %f\r\n", counter, fcounter, dcounter); counter++; fcounter += 0.01; dcounter += 0.01; temp32 = 0; } } int main(void) { clock_setup(); gpio_setup(); usart_setup(); systick_setup(); while (1) __asm__("nop"); return 0; }