AirBootGSM : An AVR & Arduino GSM OTA Bootloader

AirBootGSM is a AVR & Arduino bootloader for upgrading firmware over the air using GSM modem. It is kind of fail-safe. If anything wrong happens and the chip does not boot after the firmware upgrade, the bootloader automatically retries to download and reinstall new firmware. AirBootGSM is based on highly optimized Optiboot Bootloader.

Setup Toolchain to Compile :

sudo apt-get update
sudo apt-get install binutils gcc-avr avr-libc uisp avrdude flex byacc bison

Compile :

Run build.sh

./build.sh

Or select your traget mcu and run the following commands.

# Select Your Target MCU
TARGET_SPEED="8MHz"
# TARGET_SPEED="16MHZ"

TARGET_MCU="atmega16"
# TARGET_MCU="atmega168"
# TARGET_MCU="atmega328p"  #TESTED
# TARGET_MCU="atmega1284p"
TARGET=$TARGET_MCU"_"$TARGET_SPEED

make clean
make $TARGET

To Pragram :

Run build.sh

./build.sh

Or select your programmer and run the following commands.

PROGRAMMER="usbasp"
# PROGRAMMER="arduino"
# PROGRAMMER="avrisp"
# PROGRAMMER="avrispmkII"
avrdude -c $PROGRAMMER -p $TARGET_MCU -u -U flash:w:"AirBootGSM"_$TARGET.hex

How To Use

To use the OTA firmware upgrade capabilities from application layer, you can use the provided Arduino library. The library contains a simple example to demonstrate OTA firmware upgrade from application layer. It triggers OTA firmware upgrade if it gets input string "OTA" the from Serial.

#include "AirBootGSMLib.h"

AirBoot airboot;

int x = 0;
char buff[128];
uint16_t ota_port = 8888;
uint8_t ota_server[4] = { 192, 56, 12, 5 };

// the setup function runs once when you press reset or power the board
void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
  delay(100);
  Serial.begin(115200);
  delay(100);
  Serial.println("\r\n-- Application Starts --");
  airboot.stop_ota();
  airboot.setGsmEnablePin(PORTB, PB3);
  memset(buff, 0x00, 128);
}

// the loop function runs over and over again forever
void loop() {
  Serial.println("Loop Starts");
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, HIGH);
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);
  delay(1000);                       // wait for a second

  if(Serial.available()){
      char c = (char)Serial.read();
      buff[x] = c;
      x = ((x+1) % 128);
  }

  if(strstr(buff, "OTA")){
    Serial.println("Starting OTA .....\r\n");
    airboot.startOta(ota_server, ota_port);
  }
}

Limitations :

Currently it only supports Neoway GSM modems that support Transparet TCP mode. To keep compiled binary as small as possible to fit with a few KBs, readability of the code is greatly hampared. Still any other modems can easily be adopted.