DA14531MOD Bluetooth keyboard for iOS and Android

Question

Hello, 
 I'm developing a BLE HID keyboard with few buttons. I started with BLE SDK6 example "HID-Gamepad-digitizer", removed joysticks and digitizer functionality, changed the report descriptor to report as a keyboard. It works on Android. I have mapped 4 buttons to type letters a,b,c,d. 
 
 First question - it does not work on iOS (iphone 11). I can connect and pair, but that's it. When I try to type in the app (e.g. web browser) - it does nothing. 
 Second question - when I use it with android, I need to pair again after BLE device power cycle. What I need to do to make the device reconnect automatically after power cycle?

OV_Renesas · Accepted Answer

Hi There, Thank you for posting your question online. Could you please clarify which SDK version you are working with? 
 Justinas Zet said: First question - it does not work on iOS (iphone 11). I can connect and pair, but that's it. When I try to type in the app (e.g. web browser) - it does nothing. 
 Have you tried to attach the debugger and see if the source code is stuck? Have you tried to add BKPT and if the Keyboard functions are executed? Also, a BLE Sniffer capture would be helpful, so we can see which packets are being transferred over the air. 
 Justinas Zet said: Second question - when I use it with android, I need to pair again after BLE device power cycle. What I need to do to make the device reconnect automatically after power cycle? 
 1) The Connection is initiated by the Central device (SmartPhone) by sending the CONNECT_IND packet. So, the application you have developed, should scan, find the DA14531 and initiate the connection. 2) You stated that you need to pair again, that should only happen during the first connection. Could you please share the security configuration you have made for this project? Best Regards, OV_Renesas

OV_Renesas · Answer

HI There, Thank you for the reply and apologies for the delay. 
 Justinas Zet said: The program works when loading from RAM and it pairs once, shows the passkey on phone and when restarting BLE on phone it just reconnects. After trying to write the program to the flash it bricks the module and I can not access it via SWD, I will try to use UART to delete onboard flash. 
 Have you modified the SWD pins? During the pairing procedure, the necessary security information (BD address, LTK, IRK, etc) will be stored in the Bonding Table in the SPI Flash or in the I2C EEPROM. For the DA14531MOD, the Bonding Table is stored at the end of the SPI Flash. You should use 1-Wire UART to access the SPI Flash and delete the firmware. 
 Justinas Zet said: Was something wrong with MCU using flash to run the code and to store the info of the phone (for reconnection)? How can I avoid this? 
 I will need to understand your security configurations and if you have set the Security/Bonding callback functions as shown in the ble_app_security example. 
 Justinas Zet said: What is the minimum security requirements to reconnect automatically after power cycle? 
 If you have performed the pairing procedure, the next time the central attempts the reconnection, the DA14531 should connect automatically without going through the pairing procedure again. Best Regards, OV_Renesas

DA14531MOD Bluetooth keyboard for iOS and Android

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