246 lines
9.9 KiB
C
246 lines
9.9 KiB
C
/** library to send data using ESP8266 WiFi SoC
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* @file
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @copyright SPDX-License-Identifier: GPL-3.0-or-later
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* @date 2016-2021
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* @note peripherals used: USART @ref radio_esp8266_usart
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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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#include <string.h> // string and memory utilities
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#include <stdio.h> // string 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/usart.h> // universal synchronous asynchronous receiver transmitter library
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#include <libopencm3/cm3/nvic.h> // interrupt handler
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#include <libopencmsis/core_cm3.h> // Cortex M3 utilities
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#include "radio_esp8266.h" // radio header and definitions
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#include "global.h" // common methods
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/** @defgroup radio_esp8266_usart USART peripheral used for communication with radio
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* @{
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*/
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#define RADIO_ESP8266_USART 2 /**< USART peripheral */
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#define RADIO_ESP8266_TX PA2 /**< pin used for USART TX */
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#define RADIO_ESP8266_RX PA3 /**< pin used for USART RX */
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#define RADIO_ESP8266_AF GPIO_AF7 /**< alternate function for UART pins */
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/** @} */
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// input and output buffers and used memory
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static uint8_t rx_buffer[24] = {0}; /**< buffer for received data (we only expect AT responses) */
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static volatile uint16_t rx_used = 0; /**< number of byte in receive buffer */
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static uint8_t tx_buffer[256] = {0}; /**< buffer for data to transmit */
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static volatile uint16_t tx_used = 0; /**< number of bytes used in transmit buffer */
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// response status
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volatile bool radio_esp8266_response = false; /**< when a response has been received (OK or ERROR) */
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volatile bool radio_esp8266_success = false; /**< if the response is OK (else ERROR), set when radio_esp8266_response is set to true */
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/** transmit data to radio
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* @param[in] data data to transmit
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* @param[in] length length of data to transmit
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*/
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static void radio_esp8266_transmit(const uint8_t* data, uint8_t length) {
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while (tx_used || !usart_get_flag(USART(RADIO_ESP8266_USART), USART_SR_TXE)) { // wait until ongoing transmission completed
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usart_enable_tx_interrupt(USART(RADIO_ESP8266_USART)); // enable transmit interrupt
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__WFI(); // sleep until something happened
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}
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usart_disable_tx_interrupt(USART(RADIO_ESP8266_USART)); // ensure transmit interrupt is disable to prevent index corruption (the ISR should already have done it)
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radio_esp8266_response = false; // reset status because of new activity
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for (tx_used = 0; tx_used < length && tx_used < LENGTH(tx_buffer); tx_used++) { // copy data
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tx_buffer[tx_used] = data[length - 1 - tx_used]; // put character in buffer (in reverse order)
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}
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if (tx_used) {
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usart_enable_tx_interrupt(USART(RADIO_ESP8266_USART)); // enable interrupt to send bytes
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}
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}
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bool radio_esp8266_setup(void)
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{
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// configure pins
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rcc_periph_clock_enable(GPIO_RCC(RADIO_ESP8266_TX)); // enable clock for USART TX pin port peripheral
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gpio_mode_setup(GPIO_PORT(RADIO_ESP8266_TX), GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN(RADIO_ESP8266_TX)); // set TX pin to alternate function
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gpio_set_output_options(GPIO_PORT(RADIO_ESP8266_TX), GPIO_OTYPE_PP, GPIO_OSPEED_25MHZ, GPIO_PIN(RADIO_ESP8266_TX)); // set TX pin output as push-pull
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gpio_set_af(GPIO_PORT(RADIO_ESP8266_TX), RADIO_ESP8266_AF, GPIO_PIN(RADIO_ESP8266_TX)); // set alternate function to USART
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rcc_periph_clock_enable(GPIO_RCC(RADIO_ESP8266_RX)); // enable clock for USART RX pin port peripheral
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gpio_mode_setup(GPIO_PORT(RADIO_ESP8266_RX), GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN(RADIO_ESP8266_RX)); // set GPIO to alternate function, with pull up to avoid noise in case it is not connected
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gpio_set_af(GPIO_PORT(RADIO_ESP8266_RX), RADIO_ESP8266_AF, GPIO_PIN(RADIO_ESP8266_RX)); // set alternate function to USART
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// configure USART
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rcc_periph_clock_enable(RCC_USART(RADIO_ESP8266_USART)); // enable clock for USART peripheral
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rcc_periph_reset_pulse(RST_USART(RADIO_ESP8266_USART)); // reset peripheral
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usart_set_baudrate(USART(RADIO_ESP8266_USART), 115200);
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usart_set_databits(USART(RADIO_ESP8266_USART), 8);
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usart_set_stopbits(USART(RADIO_ESP8266_USART), USART_STOPBITS_1);
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usart_set_mode(USART(RADIO_ESP8266_USART), USART_MODE_TX_RX);
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usart_set_parity(USART(RADIO_ESP8266_USART), USART_PARITY_NONE);
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usart_set_flow_control(USART(RADIO_ESP8266_USART), USART_FLOWCONTROL_NONE);
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nvic_enable_irq(USART_IRQ(RADIO_ESP8266_USART)); // enable the UART interrupt
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usart_enable_rx_interrupt(USART(RADIO_ESP8266_USART)); // enable receive interrupt
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usart_enable(USART(RADIO_ESP8266_USART)); // enable UART
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// reset buffer states
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rx_used = 0;
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tx_used = 0;
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// verify if ESP8266 is reachable
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uint16_t timeout = 0; // reset timeout counter
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radio_esp8266_transmit((uint8_t*)"AT\r\n", 4); // verify if module is present
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while (!radio_esp8266_response) { // wait for response
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if (timeout > 100) { // response takes too long
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return false;
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}
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sleep_ms(10); // wait a tiny bit
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timeout += 10; // remember we waited
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}
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if (!radio_esp8266_success) {
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return false;
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}
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// reset module so it connects to AP
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timeout = 0; // reset timeout counter
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radio_esp8266_transmit((uint8_t*)"AT+RST\r\n", 8); // reset module
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while (!radio_esp8266_response) { // wait for response
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if (timeout > 100) { // response takes too long
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return false;
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}
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sleep_ms(10); // wait a tiny bit
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timeout += 10; // remember we waited
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}
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if (!radio_esp8266_success) {
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return false;
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}
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timeout = 0; // reset timeout counter
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while(rx_used < 13 || 0 != memcmp((char*)&rx_buffer[rx_used - 13], "WIFI GOT IP\r\n", 13)) { // wait to have IP
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if (timeout > 10000) { // connection takes too long
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return false;
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}
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sleep_ms(10); // wait a tiny bit
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timeout += 10; // remember we waited
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}
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// disable echo for better parsing
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timeout = 0; // reset timeout counter
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while (!radio_esp8266_response) { // wait for response
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if (timeout > 100) { // response takes too long
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return false;
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}
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sleep_ms(10); // wait a tiny bit
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timeout += 10; // remember we waited
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}
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if (!radio_esp8266_success) {
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return false;
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}
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return true;
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}
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bool radio_esp8266_open(const char* host, uint16_t port, bool tcp)
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{
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char command[256] = {0}; // string to create command
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int length = snprintf(command, LENGTH(command), "AT+CIPSTART=\"%s\",\"%s\",%u\r\n", tcp ? "TCP" : "UDP", host, port); // create AT command to establish a TCP connection
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if (length > 0) {
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uint16_t timeout = 0; // reset timeout counter
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radio_esp8266_transmit((uint8_t*)command, length);
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while (!radio_esp8266_response) { // wait for response
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if (timeout > 1000) { // response takes too long
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return false;
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}
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sleep_ms(10); // wait a tiny bit
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timeout += 10; // remember we waited
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}
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if (!radio_esp8266_success) {
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return false;
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}
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}
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return true;
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}
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bool radio_esp8266_send(const uint8_t* data, uint8_t length)
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{
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char command[16 + 1] = {0}; // string to create command
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int command_length = snprintf(command, LENGTH(command), "AT+CIPSEND=%u\r\n", length); // create AT command to send data
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if (command_length > 0) {
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// start sending
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uint16_t timeout = 0; // reset timeout counter
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radio_esp8266_transmit((uint8_t*)command, command_length); // transmit AT command
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while (!radio_esp8266_response) { // wait for response
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if (timeout > 1000) { // response takes too long
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return false;
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}
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sleep_ms(10); // wait a tiny bit
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timeout += 10; // remember we waited
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}
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if (!radio_esp8266_success) {
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return false;
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}
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// send actual data
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timeout = 0; // reset timeout counter
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radio_esp8266_transmit(data, length); // transmit data
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while (!radio_esp8266_response) { // wait for response
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if (timeout > 1000) { // response takes too long
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return false;
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}
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sleep_ms(10); // wait a tiny bit
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timeout += 10; // remember we waited
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}
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if (!radio_esp8266_success) {
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return false;
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}
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}
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return true;
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}
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bool radio_esp8266_close(void)
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{
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uint16_t timeout = 0; // reset timeout counter
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radio_esp8266_transmit((uint8_t*)"AT+CIPCLOSE\r\n", 13); // send AT command to close established connection
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while (!radio_esp8266_response) { // wait for response
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if (timeout > 1000) { // response takes too long
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return false;
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}
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sleep_ms(10); // wait a tiny bit
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timeout += 10; // remember we waited
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}
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if (!radio_esp8266_success) {
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return false;
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}
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return true;
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}
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/** USART interrupt service routine called when data has been transmitted or received */
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void USART_ISR(RADIO_ESP8266_USART)(void)
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{
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if (usart_get_flag(USART(RADIO_ESP8266_USART), USART_SR_TXE)) { // data has been transmitted
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if (tx_used) { // there is still data in the buffer to transmit
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usart_send(USART(RADIO_ESP8266_USART), tx_buffer[tx_used - 1]); // put data in transmit register
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tx_used--; // update used size
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} else { // no data in the buffer to transmit
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usart_disable_tx_interrupt(USART(RADIO_ESP8266_USART)); // disable transmit interrupt
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}
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}
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if (usart_get_flag(USART(RADIO_ESP8266_USART), USART_SR_RXNE)) { // data has been received
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while (rx_used >= LENGTH(rx_buffer)) { // if buffer is full
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memmove(rx_buffer, &rx_buffer[1], LENGTH(rx_buffer) - 1); // drop old data to make space (ring buffer are more efficient but harder to handle)
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rx_used--; // update used buffer information
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}
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rx_buffer[rx_used++] = usart_recv(USART(RADIO_ESP8266_USART)); // put character in buffer
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// if the used send a packet with these strings during the commands detection the AT command response will break (AT commands are hard to handle perfectly)
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if (rx_used >= 4 && 0 == memcmp((char*)&rx_buffer[rx_used - 4], "OK\r\n", 4)) { // OK received
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radio_esp8266_response = true; // response received
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radio_esp8266_success = true; // command succeeded
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rx_used = 0; // reset buffer
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} else if (rx_used >= 7 && 0 == memcmp((char*)&rx_buffer[rx_used - 7], "ERROR\r\n", 7)) { // ERROR received
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radio_esp8266_response = true; // response received
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radio_esp8266_success = false; // command failed
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rx_used = 0; // reset buffer
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}
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}
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}
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