Austin Blackstone
This is an mbed side application meant to demonstrate how to create a custom GATT service/characteristic with Evothings.
Dependencies: BLE_API mbed nRF51822
Intro
This code is meant to be run on an mbed enabled BLE board and paired with the mbed-evothings-customGATT smartphone application.
Details
This code is a demonstration of how to create a custom service (UUID=0xA0000) with two characteristics, a read only characteristic (UUID=0xA001) and a write characteristic (UUID=0xA002). What is written to the write characteristic will be copied across to the read characteristic and broadcast out. If a single byte is written it will be used to toggle the on board LED, if more than 1 byte is written the data will be written out to the terminal. The default max size is 10bytes.
Viewing Data
You can use either the LightBlue app on iOS or the nRF Master Control Panel application on Android to view the advertising data. Alternatively you can use a custom Evothings App to view the data.
Evothings?
Evothings is a rapid prototyping environment that uses cordova to enable you to rapidly develop smartphone applications in Javascript. Please download the Evothings workbench to your computer and the Evothings client to your smartphone. Then grab the code from the github page, drag and drop the index.htm file into Evothings workbench and run it on the Evothings client.
Reference
Diff: main.cpp
- Revision:
- 8:60ede963dfe2
- Parent:
- 7:f6814152873c
- Child:
- 9:b33f42191584
--- a/main.cpp Mon Mar 09 15:25:43 2015 +0000
+++ b/main.cpp Mon Mar 09 19:06:45 2015 +0000
@@ -2,50 +2,66 @@
#include "BLEDevice.h"
#include "CustomService.h"
-
-// BLE object
BLEDevice ble;
-
-// LED object
DigitalOut led(LED1);
const static char DEVICE_NAME[] = "ChangeMe!!"; // change this
-static const uint16_t uuid16_list[] = {0xFFFF}; //Custom UUID, FF is reserved for development
+static const uint16_t uuid16_list[] = {0xFFFF}; //Custom UUID, FFFF is reserved for development
// Set Up Characteristics
-static uint8_t readValue[1] = {0x00};
-GattCharacteristic readChar(0xAAAA /* read char UUID*/, readValue, sizeof(readValue), sizeof(readValue),
- GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);
+static uint8_t readValue[10] = {0x00};
+GattCharacteristic readChar(0xA001 /* read char UUID*/, readValue, sizeof(readValue), sizeof(readValue),
+ GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);
-static uint8_t writeValue[1] = {0x00};
-GattCharacteristic writeChar(0xBBBB /*write char UUID*/, writeValue, sizeof(writeValue), sizeof(writeValue),
- GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);
-
-GattCharacteristic *characteristics[] = {&readChar, &writeChar};
+static uint8_t writeValue[10] = {0x00};
+GattCharacteristic writeChar(0xA002 /*write char UUID*/, writeValue, sizeof(writeValue), sizeof(writeValue),
+ GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);
// Set up custom service
-GattService customService(0x221D /*Service UUID*/, characteristics, sizeof(characteristics) / sizeof(GattCharacteristic *));
+GattCharacteristic *characteristics[] = {&readChar, &writeChar};
+GattService customService(0xA000 /*Service UUID*/, characteristics, sizeof(characteristics) / sizeof(GattCharacteristic *));
-// Restart advertising when phone app disconnects
+/*
+ * Restart advertising when phone app disconnects
+*/
void disconnectionCallback(Gap::Handle_t handle, Gap::DisconnectionReason_t reason)
{
- ble.startAdvertising(); // restart advertising
+ ble.startAdvertising();
}
-// handle writes to writeCharacteristic
+/*
+ * handle writes to writeCharacteristic
+*/
void writeCharCallback(const GattCharacteristicWriteCBParams *params)
{
- led = params->data[0];
- printf("LED Written To, value=%x",params->data[0]);
- // TODO: update the readChar value to match write char, or better yet give it an english value
- // TODO: update with info from here : http://developer.mbed.org/forum/team-63-Bluetooth-Low-Energy-community/topic/5502/
+ // check to see what characteristic was written, by handle
+ if(params->charHandle == writeChar.getValueHandle()) {
+ // toggle LED if only 1 byte is written
+ if(params->len == 1) {
+ led = params->data[0];
+ }
+ // print the data if more than 1 byte is written
+ else {
+ for(int x=0; x < params->len; x++) {
+ printf("%x",params->data[x]);
+ }
+ printf("\n\r"); // print newline
+ }
+ // update the readChar with the value of writeChar
+ ble.updateCharacteristicValue(readChar.getValueHandle(),params->data,params->len);
+ }
}
+/*
+ * main loop
+*/
int
main(void)
{
- led = 1; // turn LED off
+ /* initialize stuff */
+ printf("\n\r********* Starting Main Loop *********\n\r");
+ led = 1; // turn LED off (led is inverted)
ble.init();
ble.onDisconnection(disconnectionCallback);
ble.onDataWritten(writeCharCallback); //TODO: this is not correct, figure out correct syntax
@@ -56,17 +72,12 @@
ble.accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LOCAL_NAME, (uint8_t *)DEVICE_NAME, sizeof(DEVICE_NAME)); // add name
ble.accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LIST_16BIT_SERVICE_IDS, (uint8_t *)uuid16_list, sizeof(uuid16_list)); // UUID's broadcast in advertising packet
ble.setAdvertisingInterval(160); /* 100ms; in multiples of 0.625ms. */
-
+ // add our custom service
ble.addService(customService); // Add our custom service to device
ble.startAdvertising(); // start advertising
while (true) {
ble.waitForEvent(); //Save power
}
-
-
- // TODO: impliment the rest of triggering for LED based on Write of characteristic.
- // TODO: impliment a read characteristic that sends text back to app
- // take a look at http://developer.mbed.org/teams/Bluetooth-Low-Energy/code/BLE_GroveColourSensor/file/000c8f8c7f03/main.cpp for inspiration.
-}
\ No newline at end of file
+}