Datasheet

PRELIMINARY PRODUCT SPECIFICATION
nRF24L01 Single Chip 2.4 GHz Radio Transceiver
Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.2 Page 15 of 39 March 2006
auto acknowledgement for all pipes running Enhanced ShockBurst™ has to be
enabled (EN_AA register), and the correct payload widths must be set
(RX_PW_Px registers). Addresses have to be set up as described in item 2 in the
Enhanced ShockBurst™ transmit payload chapter above.
2. Active RX mode is started by setting CE high.
3. After 130µs nRF24L01 is monitoring the air for incoming communication.
4. When a valid packet has been received (matching address and correct CRC), the
payload is stored in the RX-FIFO, and the RX_DR bit in status register is set high.
The IRQ pin will be active when RX_DR is high. RX_P_NO in status register will
indicate what data pipe the payload has been received in.
5. If auto acknowledgement is enabled, an acknowledgement is sent back.
6. MCU sets the CE pin low to enter Standby-I mode (low current mode).
7. MCU can clock out the payload data at a suitable rate via the SPI interface.
8. The device is now ready for entering TX or RX mode or power down mode.
Two way communication with payload in both directions
If payload shall be sent in both directions, the PRIM_RX register must be toggled by
redefining the device from PRX to PTX or vice versa. The controlling processors
must handle the synchronicity between a PTX and a PRX. Data buffering in both RX
FIFO and TX FIFO simultaneously is possible, but restricted to data pipes 1 to 5. The
third level in TX FIFO shall only be written in RX, TX or Standby-II mode if data is
stored in RX FIFO
Auto Acknowledgement (RX)
The auto acknowledgement function reduces the load of the external microcontroller,
and may remove the need for dedicated SPI hardware in a mouse/keyboard or
comparable systems, and hence reduce cost and average current consumption. Auto
acknowledgement can be configured individually for each data pipe via the SPI
interface.
If auto acknowledgement is enabled and a valid packet (correct data pipe address and
CRC) is received, the device will enter TX mode and send an acknowledgement
packet. After the device has sent the acknowledgement packet, normal operation
resumes, and the mode is determined by the PRIM_RX register and CE pin.
Auto Re-Transmission (ART) (TX)
An auto retransmission function is available. It will be used at the TX side in an auto
acknowledgement system. In the SETUP_RETR register it will be possible to state
how many times the data in the data register will be resent if data is not
acknowledged. After each sending, the device will enter RX mode and wait a
specified time period for acknowledgement. When the acknowledgement packet is
received, the device will return to normal transmit function. If there is no more unsent
data in the TX FIFO and the CE pin is low, the device will go into Standby-I mode. If
the acknowledgement is not received, the device will go back to TX mode and resend
the data. This will continue until acknowledgment is received, or a time out occurs