The design description contains details about the hardware blocks on the Smart Remote 3
for nRF51 product example.
I/O usage
The nRF51822-QFAA has 31 generic I/Os available. All I/Os are used in this design and are organized as shown in table below.
Keypad matrix
The keypad on the PCA20018 board has 39 buttons.
Low-power accelerometer circuit
To obtain low-power consumption and long battery lifetime, a low-power three-axis accelerometer (U4) has been added to the remote control.
Motion tracking device
For advanced features, the remote control has a three-axis gyro integrated with a three-axis accelerometer (U3).
Power supply
The Smart Remote 3 product example is powered by two AA batteries.
Codec
The CODEC is used to digitize and code the signal from the analog microphone.
Programming interface
A connector for the ARM SWD interface is included on the product example for easy firmware upgrade purposes.
Matching network
The design is using an integrated balun from Johanson Technology for converting from differential to single-ended signal and transforming the impedance to 50 Ω.
Antenna
The product example has an integrated chip antenna from Johanson Technology.