Datasheet
Page 27 of 161
nRF8001 Product Specification
Revision 1.2
7.2 Active signal
The active signal is an information signal provided by nRF8001. It indicates that the nRF8001 radio is
active. The active signal can be used for the following purposes:
• As a trigger for the application controller to do any activity before the radio becomes active. See
Figure 14.
• To limit activity in the application controller to maintain minimum peak current load on the battery.
• To limit noise from the application affecting the radio transmissions by separating in the time domain
the radio transmissions and application controller activity.
Its polarity can be configured active high or active low. When the active signal is asserted, nRF8001 will
drain peak currents as described in chapter 13 on page 39
. The active signal can be configured to assert
up to 20 ms before the nRF8001 radio is switched on, see Figure 14.
Jitter on this signal is ± 312.5 µs and
the signal may occur early by up to 0.1% of the interval length, as a result of a 32.768 kHz oscillator drift.
Figure 14. Active signal
Active signal is unavailable for advertising or connection intervals less than 30 ms regardless of prior
configuration. If the active signal is enabled and the connection interval or advertising interval is below
30 ms, the active signal is automatically disabled. If a subsequent connection update increases the interval
30 ms, the active signal will automatically be re-enabled without a need for reconfiguration.
When both Slave Latency and the Active Signal are enabled, the Active signal will be present on every
event to indicate that the processor is still active and consuming current.
7.3 Direct Test Mode interface
The Direct Test Mode (DTM) enables testing of the RF parameters of a Bluetooth low energy radio design.
All
Bluetooth low energy end products must include access to the DTM UART interface for end-product
qualification testing of the RF transceiver layer.
The DTM has two modes of operation; the transmit test mode and the receive test mode. In transmit test
mode, nRF8001 generates a predefined set of test packets. In receive test mode, nRF8001 counts the
number of test packets received from a dedicated RF transceiver tester.
The nRFgo Studio enables RF transceiver testing using the DTM. For more information, visit
www.nordicsemi.com
. The Bluetooth low energy Direct Test Mode implemented in nRF8001 is described in
the
Bluetooth Core specification v4.0, Vol. 6, Part F.
0-20ms + jitter Radio Active
Active signal