radio_esp8266.c
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/* 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 <http://www.gnu.org/licenses/>.
*
*/
/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdlib.h> // general utilities
#include <string.h> // string and memory utilities
#include <stdio.h> // string utilities
/* STM32 (including CM3) libraries */
#include <libopencm3/stm32/rcc.h> // real-time control clock library
#include <libopencm3/stm32/gpio.h> // general purpose input output library
#include <libopencm3/stm32/usart.h> // universal synchronous asynchronous receiver transmitter library
#include <libopencm3/cm3/nvic.h> // interrupt handler
#include <libopencmsis/core_cm3.h> // Cortex M3 utilities
#include "radio_esp8266.h" // radio header and definitions
#include "global.h" // common methods
#define RADIO_ESP8266_USART 2
/* input and output buffers and used memory */
static uint8_t rx_buffer[24] = {0};
static volatile uint16_t rx_used = 0;
static uint8_t tx_buffer[256] = {0};
static volatile uint16_t tx_used = 0;
volatile bool radio_esp8266_activity = false;
volatile bool radio_esp8266_success = false;
static void radio_esp8266_transmit(uint8_t* data, uint8_t length) {
while (tx_used || !usart_get_flag(USART(RADIO_ESP8266_USART), USART_SR_TXE)) { // wait until ongoing transmission completed
usart_enable_tx_interrupt(USART(RADIO_ESP8266_USART)); // enable transmit interrupt
__WFI(); // sleep until something happened
}
usart_disable_tx_interrupt(USART(RADIO_ESP8266_USART)); // ensure transmit interrupt is disable to prevent index corruption (the ISR should already have done it)
radio_esp8266_activity = false; // reset status because of new activity
for (tx_used=0; tx_used<length && tx_used<LENGTH(tx_buffer); tx_used++) { // copy data
tx_buffer[tx_used] = data[length-1-tx_used]; // put character in buffer (in reverse order)
}
if (tx_used) {
usart_enable_tx_interrupt(USART(RADIO_ESP8266_USART)); // enable interrupt to send bytes
}
}
void radio_esp8266_setup(void)
{
/* enable USART I/O peripheral */
rcc_periph_clock_enable(RCC_AFIO); // enable pin alternate function (USART)
rcc_periph_clock_enable(USART_PORT_RCC(RADIO_ESP8266_USART)); // enable clock for USART port peripheral
rcc_periph_clock_enable(USART_RCC(RADIO_ESP8266_USART)); // enable clock for USART peripheral
gpio_set_mode(USART_PORT(RADIO_ESP8266_USART), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, USART_PIN_TX(RADIO_ESP8266_USART)); // setup GPIO pin USART transmit
gpio_set_mode(USART_PORT(RADIO_ESP8266_USART), GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN, USART_PIN_RX(RADIO_ESP8266_USART)); // setup GPIO pin USART receive
gpio_set(USART_PORT(RADIO_ESP8266_USART), USART_PIN_RX(RADIO_ESP8266_USART)); // pull up to avoid noise when not connected
/* setup USART parameters for ESP8266 AT firmware */
usart_set_baudrate(USART(RADIO_ESP8266_USART), 115200); // AT firmware 0.51 (SDK 1.5.0) uses 115200 bps
usart_set_databits(USART(RADIO_ESP8266_USART), 8);
usart_set_stopbits(USART(RADIO_ESP8266_USART), USART_STOPBITS_1);
usart_set_mode(USART(RADIO_ESP8266_USART), USART_MODE_TX_RX);
usart_set_parity(USART(RADIO_ESP8266_USART), USART_PARITY_NONE);
usart_set_flow_control(USART(RADIO_ESP8266_USART), USART_FLOWCONTROL_NONE);
nvic_enable_irq(USART_IRQ(RADIO_ESP8266_USART)); // enable the USART interrupt
usart_enable_rx_interrupt(USART(RADIO_ESP8266_USART)); // enable receive interrupt
usart_enable(USART(RADIO_ESP8266_USART)); // enable USART
/* reset buffer states */
rx_used = 0;
tx_used = 0;
radio_esp8266_activity = false;
radio_esp8266_success = false;
radio_esp8266_transmit((uint8_t*)"AT\r\n",4); // verify if module is present
while (!radio_esp8266_activity || !radio_esp8266_success) { // wait for response
__WFI(); // sleep until something happened
}
radio_esp8266_transmit((uint8_t*)"AT+RST\r\n",8); // reset module
while (!radio_esp8266_activity || !radio_esp8266_success) { // wait for response
__WFI(); // sleep until something happened
}
while(rx_used<13 || memcmp((char*)&rx_buffer[rx_used-13], "WIFI GOT IP\r\n", 13)!=0) { // wait to have IP
__WFI(); // sleep until something happened
}
radio_esp8266_transmit((uint8_t*)"ATE0\r\n",6); // disable echoing
while (!radio_esp8266_activity || !radio_esp8266_success) { // wait for response
__WFI(); // sleep until something happened
}
}
void radio_esp8266_tcp_open(char* host, uint16_t port)
{
char command[256] = {0}; // string to create command
int length = snprintf(command, LENGTH(command), "AT+CIPSTART=\"TCP\",\"%s\",%u\r\n", host, port); // create AT command to establish a TCP connection
if (length>0) {
radio_esp8266_transmit((uint8_t*)command, length);
}
}
void radio_esp8266_send(uint8_t* data, uint8_t length)
{
char command[16+1] = {0}; // string to create command
int command_length = snprintf(command, LENGTH(command), "AT+CIPSEND=%u\r\n", length); // create AT command to send data
if (command_length>0) {
radio_esp8266_transmit((uint8_t*)command, command_length); // transmit AT command
while (!radio_esp8266_activity || !radio_esp8266_success) { // wait for response
__WFI(); // sleep until something happened
}
if (!radio_esp8266_success) { // send AT command did not succeed
return; // don't transmit data
}
radio_esp8266_transmit(data, length); // transmit data
}
}
void radio_esp8266_close(void)
{
radio_esp8266_transmit((uint8_t*)"AT+CIPCLOSE\r\n", 13); // send AT command to close established connection
}
void USART_ISR(RADIO_ESP8266_USART)(void)
{
if (usart_get_interrupt_source(USART(RADIO_ESP8266_USART), USART_SR_TXE)) { // data has been transmitted
if (tx_used) { // there is still data in the buffer to transmit
usart_send(USART(RADIO_ESP8266_USART),tx_buffer[tx_used-1]); // put data in transmit register
tx_used--; // update used size
} else { // no data in the buffer to transmit
usart_disable_tx_interrupt(USART(RADIO_ESP8266_USART)); // disable transmit interrupt
}
}
if (usart_get_interrupt_source(USART(RADIO_ESP8266_USART), USART_SR_RXNE)) { // data has been received
while (rx_used>=LENGTH(rx_buffer)) { // if buffer is full
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)
rx_used--; // update used buffer information
}
rx_buffer[rx_used++] = usart_recv(USART(RADIO_ESP8266_USART)); // put character in buffer
// 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)
if (rx_used>=4 && memcmp((char*)&rx_buffer[rx_used-4], "OK\r\n", 4)==0) { // OK received
radio_esp8266_activity = true; // response received
radio_esp8266_success = true; // command succeeded
rx_used = 0; // reset buffer
} else if (rx_used>=7 && memcmp((char*)&rx_buffer[rx_used-7], "ERROR\r\n", 7)==0) { // ERROR received
radio_esp8266_activity = true; // response received
radio_esp8266_success = false; // command failed
rx_used = 0; // reset buffer
}
}
}
radio_esp8266_activity
volatile bool radio_esp8266_activity
a response has been returned by the radio
Definition: radio_esp8266.c:50
radio_esp8266_tcp_open
void radio_esp8266_tcp_open(char *host, uint16_t port)
establish TCP connection
Definition: radio_esp8266.c:117
USART_ISR
#define USART_ISR(x)
get interrupt service routine for USART based on USART identifier
Definition: global.h:188
radio_esp8266_success
volatile bool radio_esp8266_success
the last command has succeeded
Definition: radio_esp8266.c:51
radio_esp8266_transmit
static void radio_esp8266_transmit(uint8_t *data, uint8_t length)
transmit data to radio
Definition: radio_esp8266.c:57
radio_esp8266.h
library to send data using ESP8266 WiFi SoC (API)
global.h
global definitions and methods (API)
rx_used
static volatile uint16_t rx_used
number of byte in receive buffer
Definition: radio_esp8266.c:46
USART_IRQ
#define USART_IRQ(x)
get NVIC IRQ for USART based on USART identifier
Definition: global.h:186
USART
#define USART(x)
get USART based on USART identifier
Definition: global.h:182
USART_PORT
#define USART_PORT(x)
get port for USART based on USART identifier
Definition: global.h:190
USART_PORT_RCC
#define USART_PORT_RCC(x)
get RCC for USART port based on USART identifier
Definition: global.h:195
snprintf
size_t snprintf(char *str, size_t size, const char *format,...)
print format string on string or user output
Definition: print.c:455
radio_esp8266_setup
void radio_esp8266_setup(void)
setup peripherals to communicate with radio
Definition: radio_esp8266.c:72
radio_esp8266_send
void radio_esp8266_send(uint8_t *data, uint8_t length)
send data (requires established connection)
Definition: radio_esp8266.c:126
LENGTH
#define LENGTH(x)
get the length of an array
Definition: global.h:26
USART_RCC
#define USART_RCC(x)
get RCC for USART based on USART identifier
Definition: global.h:184
USART_PIN_RX
#define USART_PIN_RX(x)
get receive pin for USART based on USART identifier
Definition: global.h:202
USART_PIN_TX
#define USART_PIN_TX(x)
get transmit pin for USART based on USART identifier
Definition: global.h:200
RADIO_ESP8266_USART
#define RADIO_ESP8266_USART
USART peripheral.
Definition: radio_esp8266.c:41
rx_buffer
static uint8_t rx_buffer[24]
buffer for received data (we only expect AT responses)
Definition: radio_esp8266.c:45
tx_buffer
static uint8_t tx_buffer[256]
buffer for data to transmit
Definition: radio_esp8266.c:47
radio_esp8266_close
void radio_esp8266_close(void)
close established connection
Definition: radio_esp8266.c:142
tx_used
static volatile uint16_t tx_used
number of bytes used in transmit buffer
Definition: radio_esp8266.c:48