From b7875d0230f81df45145737f8cf46596f8bf15c6 Mon Sep 17 00:00:00 2001 From: Piotr Esden-Tempski Date: Wed, 14 Mar 2012 13:15:14 -0700 Subject: Added dma based usart IO example. --- examples/stm32/f1/lisa-m-2/usart_dma/Makefile | 25 +++ examples/stm32/f1/lisa-m-2/usart_dma/usart_dma.c | 199 +++++++++++++++++++++++ 2 files changed, 224 insertions(+) create mode 100644 examples/stm32/f1/lisa-m-2/usart_dma/Makefile create mode 100644 examples/stm32/f1/lisa-m-2/usart_dma/usart_dma.c (limited to 'examples/stm32/f1/lisa-m-2') diff --git a/examples/stm32/f1/lisa-m-2/usart_dma/Makefile b/examples/stm32/f1/lisa-m-2/usart_dma/Makefile new file mode 100644 index 0000000..813cda9 --- /dev/null +++ b/examples/stm32/f1/lisa-m-2/usart_dma/Makefile @@ -0,0 +1,25 @@ +## +## This file is part of the libopencm3 project. +## +## Copyright (C) 2009 Uwe Hermann +## +## 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 . +## + +BINARY = usart_dma + +LDSCRIPT = ../lisa-m.ld + +include ../../Makefile.include + diff --git a/examples/stm32/f1/lisa-m-2/usart_dma/usart_dma.c b/examples/stm32/f1/lisa-m-2/usart_dma/usart_dma.c new file mode 100644 index 0000000..ac3bb3c --- /dev/null +++ b/examples/stm32/f1/lisa-m-2/usart_dma/usart_dma.c @@ -0,0 +1,199 @@ +/* + * This file is part of the libopencm3 project. + * + * Copyright (C) 2009 Uwe Hermann + * + * 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 + +void clock_setup(void) +{ + rcc_clock_setup_in_hse_12mhz_out_72mhz(); + + /* Enable GPIOA, GPIOB, GPIOC clock. */ + rcc_peripheral_enable_clock(&RCC_APB2ENR, + RCC_APB2ENR_IOPAEN | RCC_APB2ENR_IOPBEN | + RCC_APB2ENR_IOPCEN); + + /* Enable clocks for GPIO port B (for GPIO_USART3_TX) and USART3. */ + rcc_peripheral_enable_clock(&RCC_APB1ENR, + RCC_APB1ENR_USART2EN); + + /* Enable DMA1 clock */ + rcc_peripheral_enable_clock(&RCC_AHBENR, RCC_AHBENR_DMA1EN); +} + +void usart_setup(void) +{ + /* Setup GPIO pin GPIO_USART2_TX and GPIO_USART2_RX. */ + gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, + GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART2_TX); + gpio_set_mode(GPIOA, GPIO_MODE_INPUT, + GPIO_CNF_INPUT_FLOAT, GPIO_USART2_RX); + + /* Setup UART parameters. */ + usart_set_baudrate(USART2, 38400); + usart_set_databits(USART2, 8); + usart_set_stopbits(USART2, USART_STOPBITS_1); + usart_set_mode(USART2, USART_MODE_TX_RX); + usart_set_parity(USART2, USART_PARITY_NONE); + usart_set_flow_control(USART2, USART_FLOWCONTROL_NONE); + + /* Finally enable the USART. */ + usart_enable(USART2); + + nvic_set_priority(NVIC_DMA1_CHANNEL7_IRQ, 0); + nvic_enable_irq(NVIC_DMA1_CHANNEL7_IRQ); + + nvic_set_priority(NVIC_DMA1_CHANNEL6_IRQ, 0); + nvic_enable_irq(NVIC_DMA1_CHANNEL6_IRQ); + +} + +void dma_write(char *data, int size) +{ + /* + * Using channel 7 for USART2_TX + */ + + /* Reset DMA channel*/ + dma_channel_reset(DMA1, DMA_CHANNEL7); + + dma_set_peripheral_address(DMA1, DMA_CHANNEL7, (u32)&USART2_DR); + dma_set_memory_address(DMA1, DMA_CHANNEL7, (u32)data); + dma_set_number_of_data(DMA1, DMA_CHANNEL7, size); + dma_set_read_from_memory(DMA1, DMA_CHANNEL7); + dma_enable_memory_increment_mode(DMA1, DMA_CHANNEL7); + dma_set_peripheral_size(DMA1, DMA_CHANNEL7, DMA_CCR_PSIZE_8BIT); + dma_set_memory_size(DMA1, DMA_CHANNEL7, DMA_CCR_MSIZE_8BIT); + dma_set_priority(DMA1, DMA_CHANNEL7, DMA_CCR_PL_VERY_HIGH); + + dma_enable_transfer_complete_interrupt(DMA1, DMA_CHANNEL7); + + dma_enable_channel(DMA1, DMA_CHANNEL7); + + usart_enable_tx_dma(USART2); +} + +volatile int transfered = 0; + +void dma1_channel7_isr(void) +{ + if ((DMA1_ISR &DMA_ISR_TCIF7) != 0) { + DMA1_IFCR |= DMA_IFCR_CTCIF7; + + transfered = 1; + } + + dma_disable_transfer_complete_interrupt(DMA1, DMA_CHANNEL7); + + usart_disable_tx_dma(USART2); + + dma_disable_channel(DMA1, DMA_CHANNEL7); +} + +void dma_read(char *data, int size) +{ + /* + * Using channel 6 for USART2_RX + */ + + /* Reset DMA channel*/ + dma_channel_reset(DMA1, DMA_CHANNEL6); + + dma_set_peripheral_address(DMA1, DMA_CHANNEL6, (u32)&USART2_DR); + dma_set_memory_address(DMA1, DMA_CHANNEL6, (u32)data); + dma_set_number_of_data(DMA1, DMA_CHANNEL6, size); + dma_set_read_from_peripheral(DMA1, DMA_CHANNEL6); + dma_enable_memory_increment_mode(DMA1, DMA_CHANNEL6); + dma_set_peripheral_size(DMA1, DMA_CHANNEL6, DMA_CCR_PSIZE_8BIT); + dma_set_memory_size(DMA1, DMA_CHANNEL6, DMA_CCR_MSIZE_8BIT); + dma_set_priority(DMA1, DMA_CHANNEL6, DMA_CCR_PL_HIGH); + + dma_enable_transfer_complete_interrupt(DMA1, DMA_CHANNEL6); + + dma_enable_channel(DMA1, DMA_CHANNEL6); + + usart_enable_rx_dma(USART2); +} + +volatile int received = 0; + +void dma1_channel6_isr(void) +{ + if ((DMA1_ISR &DMA_ISR_TCIF6) != 0) { + DMA1_IFCR |= DMA_IFCR_CTCIF6; + + received = 1; + } + + dma_disable_transfer_complete_interrupt(DMA1, DMA_CHANNEL6); + + usart_disable_rx_dma(USART2); + + dma_disable_channel(DMA1, DMA_CHANNEL6); +} + +void gpio_setup(void) +{ + /* Set GPIO8 (in GPIO port A) to 'output push-pull'. */ + gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_2_MHZ, + GPIO_CNF_OUTPUT_PUSHPULL, GPIO8); +} + +int main(void) +{ + char tx[10] = "abcdefg\r\n"; + int tx_len = 10; + char rx[7] = "bcdefg"; + int rx_len = 6; + + clock_setup(); + gpio_setup(); + usart_setup(); + + transfered = 0; + dma_write(tx, tx_len); + received = 0; + dma_read(rx, rx_len); + + /* Blink the LED (PA8) on the board with every transmitted byte. */ + while (1) { + gpio_toggle(GPIOA, GPIO8); /* LED on/off */ + while ( transfered != 1) { + if (received == 1) { + tx[1] = rx[0]; + tx[2] = rx[1]; + tx[3] = rx[2]; + tx[4] = rx[3]; + tx[5] = rx[4]; + tx[6] = rx[5]; + received = 0; + dma_read(rx, rx_len); + } + } + tx[0]++; + if (tx[0] > 'z') tx[0] = 'a'; + transfered = 0; + dma_write(tx, tx_len); + } + + return 0; +} -- cgit v1.2.3