111 lines
5.0 KiB
C
111 lines
5.0 KiB
C
/* 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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*/
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/** library to control multiple software USARTs (code)
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* @file usart_soft.c
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2016
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* @note peripherals used: GPIO @ref usart_soft_gpio, timer @ref usart_soft_timer
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*/
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/* standard libraries */
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#include <stdint.h> // standard integer types
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#include <stdlib.h> // general utilities
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/* STM32 (including CM3) libraries */
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#include <libopencm3/stm32/rcc.h> // real-time control clock library
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#include <libopencm3/stm32/gpio.h> // general purpose input output library
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#include <libopencm3/stm32/timer.h> // timer library
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#include <libopencm3/cm3/nvic.h> // interrupt handler
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#include "usart_soft.h" // software USART library API
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#include "global.h" // common methods
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/** @defgroup usart_soft_gpio GPIO used for the software USART ports
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* @{
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*/
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static const uint32_t usart_soft_rx_ports[USART_SOFT_RX_PORTS] = {0}; /**< GPIO ports for receive signals */
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static const uint32_t usart_soft_rx_pins[USART_SOFT_RX_PORTS] = {0}; /**< GPIO pins for receive signals */
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static const uint32_t usart_soft_tx_ports[USART_SOFT_TX_PORTS] = {0}; /**< GPIO ports for transmit signals */
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static const uint32_t usart_soft_tx_pins[USART_SOFT_TX_PORTS] = {0}; /**< GPIO pins for transmit signals */
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/** @} */
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/** @defgroup usart_soft_config USART configurations
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* @note this implementation is designed for 8 bits, no parity, any stop configuration since this is the most common case
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* @{
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*/
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static const uint32_t usart_soft_rx_baudrates[USART_SOFT_RX_PORTS] = {9600}; /**< receive signal baudrates (2400-115200) */
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static const uint32_t usart_soft_tx_baudrates[USART_SOFT_TX_PORTS] = {0}; /**< transmit signal baudrates (2400-115200) */
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/** @} */
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/** @defgroup usart_soft_timer timer used to same USART signals
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* @{
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*/
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#define USART_SOFT_RX_TIMER 3 /**< timer peripheral for receive signals */
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#define USART_SOFT_TX_TIMER 4 /**< timer peripheral for transmit signals */
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/** @} */
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bool usart_soft_setup(void)
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{
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// verify configuration
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if ((USART_SOFT_RX_PORTS<0) || (USART_SOFT_RX_PORTS>4)) {
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return false;
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}
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if ((USART_SOFT_TX_PORTS<0) || (USART_SOFT_TX_PORTS>4)) {
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return false;
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}
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for (uint8_t i = 0; i < USART_SOFT_RX_PORTS; i++) {
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if ((usart_soft_rx_baudrates[i]<2400) || (usart_soft_rx_baudrates[i]>115200)) {
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return false;
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}
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}
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for (uint8_t i = 0; i < USART_SOFT_TX_PORTS; i++) {
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if ((usart_soft_tx_baudrates[i]<2400) || (usart_soft_tx_baudrates[i]>115200)) {
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return false;
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}
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}
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// setup GPIOs
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for (uint8_t i = 0; i < USART_SOFT_RX_PORTS; i++) {
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rcc_periph_clock_enable(RCC_GPIO[usart_soft_rx_ports[i]]); // enable clock for GPIO peripheral
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gpio_set_mode(GPIO_PORT[usart_soft_rx_ports[i]], GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, GPIO_PIN(usart_soft_rx_pins[i])); // setup GPIO pin USART receive
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gpio_set(GPIO_PORT[usart_soft_rx_ports[i]], GPIO_PIN(usart_soft_rx_pins[i])); // pull up to avoid noise when not connected
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}
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for (uint8_t i = 0; i < USART_SOFT_TX_PORTS; i++) {
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rcc_periph_clock_enable(RCC_GPIO[usart_soft_tx_ports[i]]); // enable clock for GPIO peripheral
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gpio_set_mode(GPIO_PORT[usart_soft_tx_ports[i]], GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO_PIN(usart_soft_tx_pins[i])); // setup GPIO pin USART transmit
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}
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// setup timer
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if (USART_SOFT_RX_PORTS>0) {
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rcc_periph_clock_enable(RCC_TIM[USART_SOFT_RX_TIMER]); // enable clock for timer peripheral
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timer_reset(TIM[USART_SOFT_RX_TIMER]); // reset timer state
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timer_set_mode(TIM[USART_SOFT_RX_TIMER], TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock, edge alignment (simple count), and count up
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timer_set_prescaler(TIM[USART_SOFT_RX_TIMER], 0); // prescaler to be able to sample 2400-115200 bps (72MHz/2^16=1099<2400bps)
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nvic_enable_irq(NVIC_TIM_IRQ[USART_SOFT_RX_TIMER]); // allow interrupt for timer
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}
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if (USART_SOFT_TX_PORTS>0) {
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rcc_periph_clock_enable(RCC_TIM[USART_SOFT_TX_TIMER]); // enable clock for timer peripheral
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timer_reset(TIM[USART_SOFT_TX_TIMER]); // reset timer state
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timer_set_mode(TIM[USART_SOFT_TX_TIMER], TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock, edge alignment (simple count), and count up
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timer_set_prescaler(TIM[USART_SOFT_TX_TIMER], 0); // prescaler to be able to sample 2400-115200 bps (72MHz/2^16=1099<2400bps)
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nvic_enable_irq(NVIC_TIM_IRQ[USART_SOFT_TX_TIMER]); // allow interrupt for timer
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}
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return true; // setup completed
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}
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void TIM_ISR(USART_SOFT_RX_TIMER)(void)
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{
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}
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