I have a general question to Bluetooth dual mode (also known as Bluetooth Smart Ready) module (such as the BT121). As I know, Bluetooth Dual mode support both, the "classic Bluetooth" (BR/EDR) and also the "low energy Bluetooth". The scenario is: The module (e.g. BT121) is set to "Advertising, connectable" mode in "Low Energy" mode and operates as Slave. Now the module send periodic advertising Messages. My question: Is the module in this scenario also visible for other bluetooth moduls, which didn't support the "Low Energy" function (e.g. Bluetooth 3.0 module)? Or is there a possibility that the module is visible for both, "Low Energy" module and "classic bluetooth" module at the same time? How high is then the average current consumption of this module?
When the module is simply transmitting BLE advertising packets then it will be seen only by BLE scanning Masters. So only BLE-enabled devices will be capable of seeing it, like Smart or Smart-Ready devices.
Good news is that the stack in the BT121 can make the module also visible (and connectable) to Bluetooth Classic-only devices at the same time.
Commands to start BLE advertisements and to make the module visible to Classic devices are le_gap_set_mode and bt_gap_set_mode. These commands can be launched one after the other like it happens for example in the BGScript of the demo firmware pre-installed in the evaluation kit modules (such demo firmware being obtained from the project files under the directory \example\bgdemo\ of the SDK)
When it comes to current consumption it strongly depends on the advertising interval and if power saving modes are enabled or not.
Thanks for your fast reply.
I'm quite new in the Bluetooth Smart/Smart Ready topic and so i have another question. I read that two "Bluetooth Smart Ready" devices can only send data to each other over the "classic Bluetooth" (BR/EDR) function. Is that true? Or is it possible, that these devices also send data to each other over the "Bluetooth low energy" function? And what's about the visibility - if both Bluetooth Smart Ready modules (e.g. BT121) operates just in the "Low Energy function" and set in the "visible, connectable"- mode, are the modules then visible for each other? Or must the modules operates in both, "Low Energy function" and "classic Bluetooth function" and set in the "visible, connectable"-mode for both functions, that the modules are visible for each other?
Thanks again for your support.
Can you recall where you did read about this? We have also heard that, looking at GATT based communication, if at some point in time both BLE and BR/EDR connections are possible between two devices, and if GATT transactions are supported by the two devices over RFCOMM/SPP then BR/EDR should be preferred. This is for example how Android works. However we have not found any mention about this in the specification.
That said, the BT121 supports GATT transactions over BR/EDR, and with modules like the BT121 you are free to select at any point in time if you want to only use BLE, or only BR/EDR, or both. When you are using both, and the other side is also using both, you still are free to open the kind of connection you like, be it BLE or BR/EDR. The same could be valid for the other side, depending on its Bluetooth implementation.