nRF24LE1 Nordic VLSI, nRF24LE1 Datasheet - Page 21

• Manufacturer Part Number: nRF24LE1
• Manufacturer: Nordic VLSI

nRF24LE1 Preliminary Product Specification
3.3.2
The air data rate is the modulated signaling rate the RF Transceiver uses when transmitting and receiving
data. It can be 250kbps, 1Mbps or 2Mbps. Using lower air data rate gives better receiver sensitivity than
higher air data rate. But, high air data rate gives lower average current consumption and reduced probabil-
ity of on-air collisions.
The air data rate is set by the RF_DR bit in the RF_SETUP register. A transmitter and a receiver must be
programmed with the same air data rate to communicate with each other.
The RF Transceiver is fully compatible with nRF24L01. For compatibility with nRF2401A, nRF2402,
nRF24E1, and nRF24E2 the air data rate must be set to 250kbps or 1Mbps.
3.3.3
The RF channel frequency determines the center of the channel used by the RF Transceiver. The channel
occupies a bandwidth of less than 1MHz at 250kbps and 1Mbps and a bandwidth of less than 2MHz at
2Mbps. The RF Transceiver can operate on frequencies from 2.400GHz to 2.525GHz. The programming
resolution of the RF channel frequency setting is 1MHz.
At 2Mbps the channel occupies a bandwidth wider than the resolution of the RF channel frequency setting.
To ensure non-overlapping channels in 2Mbps mode, the channel spacing must be 2MHz or more. At
1Mbps and 250kbps the channel bandwidth is the same or lower than the resolution of the RF frequency.
The RF channel frequency is set by the RF_CH register according to the following formula:
F
You must program a transmitter and a receiver with the same RF channel frequency to communicate with
each other.
3.3.4
Received Power Detector (RPD), located in register 09, bit 0, triggers at received power levels above -64
dBm that are present in the RF channel you receive on. If the received power is less than -64 dBm,
RDP = 0.
The RPD can be read out at any time while the RF Transceiver is in receive mode. This offers a snapshot
of the current received power level in the channel. The RPD status is latched when a valid packet is
received which then indicates signal strength from your own transmitter. If no packets are received the
RPD is latched at the end of a receive period as a result of host MCU setting rfce low or RX time out con-
trolled by Enhanced ShockBurst™.
The status of RPD is correct when RX mode is enabled and after a wait time of Tstby2a +Tdelay_AGC=
130us + 40us. The RX gain varies over temperature which means that the RPD threshold also varies over
temperature. The RPD threshold value is reduced by - 5dB at T = -40°C and increased by + 5dB at 85°C.
3.3.5
The PA (Power Amplifier) control is used to set the output power from the RF Transceiver power amplifier.
In TX mode PA control has four programmable steps, see
Revision 1.1
0
= 2400 + RF_CH MHz
Air data rate
RF channel frequency
Received Power Detector measurements
PA control
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Table 5.