nRF24LE1 Nordic VLSI, nRF24LE1 Datasheet - Page 19

• Manufacturer Part Number: nRF24LE1
• Manufacturer: Nordic VLSI

nRF24LE1 Preliminary Product Specification
Standby-II mode
In standby-II mode extra clock buffers are active and more current is used compared to standby-I mode.
The RF Transceiver enters standby-II mode if the rfce bit is held high on a PTX operation with an empty
TX FIFO. If a new packet is downloaded to the TX FIFO, the PLL immediately starts and the packet is
transmitted after the normal PLL settling delay (130µs).
The register values are maintained and the SPI can be activated during both standby modes. For start up
times see
3.3.1.4
The RX mode is an active mode where the RF Transceiver is used as a receiver. To enter this mode, the
RF Transceiver must have the PWR_UP bit, PRIM_RX bit and the rfce bit is set high.
In RX mode the receiver demodulates the signals from the RF channel, constantly presenting the demodu-
lated data to the baseband protocol engine. The baseband protocol engine constantly searches for a valid
packet. If a valid packet is found (by a matching address and a valid CRC) the payload of the packet is pre-
sented in a vacant slot in the RX FIFOs. If the RX FIFOs are full, the received packet is discarded.
The RF Transceiver remains in RX mode until the MCU configures it to standby-I mode or power down
mode. However, if the automatic protocol features (Enhanced ShockBurst™) in the baseband protocol
engine are enabled, the RF Transceiver can enter other modes in order to execute the protocol.
In RX mode a Received Power Detector (RPD) signal is available. The RPD is a signal that is set high
when a RF signal higher than -64 dBm is detected inside the receiving frequency channel. The internal
RPD signal is filtered before presented to the RPD register. The RF signal must be present for at least 40µs
before the RPD is set high. How to use the RPD is described in
3.3.1.5
The TX mode is an active mode for transmitting packets. To enter this mode, the RF Transceiver must
have the PWR_UP bit set high, PRIM_RX bit set low, a payload in the TX FIFO and a high pulse on the
rfce bit for more than 10µs.
The RF Transceiver stays in TX mode until it finishes transmitting a packet. If rfce = 0, RF Transceiver
returns to standby-I mode. If rfce = 1, the status of the TX FIFO determines the next action. If the TX
FIFO is not empty the RF Transceiver remains in TX mode and transmits the next packet. If the TX FIFO is
empty the RF Transceiver goes into standby-II mode. The RF Transceiver transmitter PLL operates in
open loop when in TX mode. It is important never to keep the RF Transceiver in TX mode for more than
4ms at a time. If the Enhanced ShockBurst™ features are enabled, RF Transceiver is never in TX mode
longer than 4ms.
Revision 1.1
Table 4. on page
RX mode
TX mode
20.
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Section 3.3.4 on page
21.