Super dry goods: Bluetooth® module usage specifications and development precautions

In this issue, MINEW has compiled a short and powerful super-dry product “Bluetooth Module Usage Specification and Development Guide”, hoping to help engineers develop Bluetooth modules!

1. Wiring problem of Bluetooth module
General Bluetooth modules use UART serial communication. The UART has two pins: TX (output) and RX (input). TX and RX refer to themselves. Your output is someone else ’s input, and your input is someone else ’s. Output, so the wiring should be crossed.
For example, the user MCU directly uses the UART serial communication method to communicate with the Bluetooth module SKB369; the SKB369 module can transparently transmit all serial port data from the user MCU to the other end device through the BLE wireless channel.

2. Power supply problem of Bluetooth module
The stability of the power supply of the Bluetooth module is a prerequisite for the normal operation of the Bluetooth chip.
The general Bluetooth module comes with a 10-22uF capacitor, which can work normally on a general stable power supply, but when some power sources are unstable, including high-power devices, and inductive devices, they often work abnormally.
At this time, you can add a larger capacitor near the power supply pin outside the module (usually the maximum current xx mA is probably xx uF capacitor is OK), this is not a hard rule, but it is recommended to add one in all use scenarios Capacitors, which try to leave room for stability.
And, for a Bluetooth module with excessive current, it is not recommended to stop the module by controlling the power supply of the Bluetooth module.

3. The antenna of the module.
The antennas of Bluetooth modules we generally see are PCB antennas, ceramic antennas and IPEX external antennas. For PCB and ceramic antennas, the upper and lower positions of the antenna are not allowed to be close to the wiring, copper clad and metal objects, because these behaviors will cause great interference to the antenna and greatly reduce the performance of the antenna. It is recommended that the antenna be protruded from the PCB outside.

4. The layout of the module.
Most Bluetooth modules use multiple rows of semi-holes (also called stamp holes). For Bluetooth modules packaged with stamp holes, everyone should pay attention to wiring: For the useless pins on the Bluetooth module, it is best not to wire under these pins . It is really necessary to perform wiring and insulation treatment to prevent short circuits from burning out the Bluetooth module or integrated circuit board.