BTM461 Development Kit
Quick Start Guide
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6
Laird Technologies
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Note the sequence that the BTM46x module has to go through. If it fails at any point the process stops and
an error message is returned.
IAP:IDPS – indicates that the IDPS process has started.
IAP:IDPS OK indicates that the IDPS process has been completed.
IAP:AUTH OK indicates that a valid authentication chip has been found on the device.
Figure 7: IAP Messages during connection
Pairing and Connecting from an Apple iOS device
Technically you cannot make an iAP/SPP connection to a BTM46x, or any other Bluetooth device, from an
Apple device. There are no API calls within the iOS operating system that allows a Bluetooth connection to be
made. The application is simply informed that a connection is available.
However, an Apple device may make a connection by first connecting over another Bluetooth profile. Then,
the BTM46x closes that connection and opens an SPP/IAP connection. The following S Registers must be set:
ATS9003=3 – Allows the BTM46x to support both the HID and SPP profiles.
ATS9089=1 – Allows the BTM46x to initiate an iAP/SPP connection upon a HID request from an Apple device.
Also, to initiate the connection from another device, the BTM46x must first be made connectable and
discoverable. To do so, you may set S Register 512 (ATS512=4) or enter the command:
AT+BTP
This ensures the BTM46x appears in the list of available devices after inquiry scan, and that it is connectable.
For these settings to persist, use the AT&W and ATZ commands.
Note: When initiating a connection from an Apple device, the connection state on the Apple screen may
change from “Connected” to “Not Connected” and then back to “Connected”. This is expected,
as there is initially an HID connection that must be closed before initiating the iAP connection.
References
1.
BTM46x_MFi_Application Note
2.
LWS-UM-BTM46X
