Page 373 - ARM Based Microcontroller Projects Using MBED

14.5 PROJECT 3—ANDROID—NUCLEO BOARD COMMUNICATION USING BLUETOOTH 359
We can modify the program in Fig. 14.27 by sending a confirmation to the mobile phone
when there is change in the LED status. The modified program listing (program:
BluetoothConfirm) is shown in Fig. 14.30 where printf statements are used to send confir-
mation to the mobile device. For example, as shown in Fig. 14.31, the text LEDB is ON is
displayed on the screen after the command ONB is sent.

/***********************************************************************
BLUETOOTH LED CONTROL
=====================

In this program a serial HC-06 Bluetooth module is connected to UART
pins PA_9 and PA_10. Additonally, two LEDs are connected to PORTC
pins PC_0 and PC_0. Commands sent from a Bluetooth device (e.g. a
mobile phone or a laptop) control the LEDs. Commands ONx turn ON
LEDs where x is A for LEDA and B for LEDB. Similarly, commands
OFFx turn OFF the LEDs where x is A fo LEDA and B for LEDB

In this version of the program, confirmation is sent back to the
mobile device when the status of an LED changes
Author: Dogan Ibrahim
Date : September 2018
File : BluetoothConfirm
**********************************************************************/
#include "mbed.h"
#define TX PA_9 // UART TX pin
#define RX PA_10 // UART RX pin
Serial bluetooth(TX, RX); // Bluetooth interface
//
// Configure the LEDs as outputs and turn them OFF at beginning
//
DigitalOut LEDA(PC_0, 0);
DigitalOut LEDB(PC_1, 0);
int main()
{
char Buffer[10];
//
// Receive commands and control the LEDs accordingly. The received
// commands are stored in character array Buffer.
//
FIG. 14.30 Modified program.
(Continued)