One of the MAGPIOs can be deployed for the antenna presence test.
In the antenna presence test, a MAGPIO is DC connected to the antenna feed. Routing from the antenna line to the RF choke inductor (L1) should be kept as short as possible to minimize parallel stub in the antenna feed. The DC block capacitor (C1) prevents DC grounding of the test signals. C2 is an RF grounding capacitor. The antenna presence test is run by an AT command that can be found in nRF91 AT Commands Reference Guide. The MAGPIO to be used for the test is defined by the AT command.
An example of the implementation is shown in Antenna presence test using MAGPIO.
Figure 1. Antenna presence test using MAGPIO
| Reference | Description |
|---|---|
| A1 | Antenna, DC grounded |
| J1 | Coaxial switch connector (Murata MM8130-2600) |
| L1 | Antenna detection, RF choke inductor (56 nH) |
| L2 | Antenna matching component (value depends on selected antenna) |
| C1 | Antenna detection, DC block |
| C2 | Antenna detection, RF grounding (56 pF) |
| C3 | Antenna matching component (value depends on selected antenna) |
| C4 | Antenna matching component (value depends on selected antenna) |
The following components are highlighted in Layout of antenna presence test using MAGPIO:
- Test connector
- Antenna matching circuit
- Antenna detection components
- Antenna keep-out area
Figure 2. Layout of antenna presence test using MAGPIO
