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 10 of 39 March 2006
FUNCTIONAL DESCRIPTION
Modes of operation
The nRF24L01 can be set in the following main modes depending on the level of the
following primary I/Os and configuration registers:
Mode
PWR_UP
register
PRIM_RX
register
CE FIFO state
RX mode 1 1 1 -
TX mode 1 0 1 Data in TX FIFO
TX mode 1 0 1Î0 Stays in TX mode until packet
transmission is finished
Standby-II 1 0 1 TX FIFO empty
Standby-I 1 - 0 No ongoing packet transmission
Power Down 0 - - -
Table 6 nRF24L01 main modes
An overview of the nRF24L01 I/O pins in different modes is given in Table 7.
Pin functions in the different modes of nRF24L01
Pin Name Direction TX Mode RX Mode Standby Modes Power Down
CE
Input High Pulse >10µs High Low -
CSN
Input SPI Chip Select, active low
SCK
Input SPI Clock
MOSI
Input SPI Serial Input
MISO
Tri-state
Output
SPI Serial Output
IRQ
Output Interrupt, active low
Table 7 Pin functions of the nRF24L01
Standby Modes
Standby-I mode is used to minimize average current consumption while maintaining
short start up times. In this mode, part of the crystal oscillator is active. In Standby-II
mode some extra clock buffers are active compared to Standby-I mode. Standby-II
occurs when CE is held high on a PTX device with empty TX FIFO. The
configuration word content is maintained during Standby modes. SPI interface may be
activated. For start up time see Table 13.
Power Down Mode
In power down nRF24L01 is disabled with minimal current consumption. When
entering this mode the device is not active, but all registers values available from the
SPI interface are maintained during power down and the SPI interface may be
activated (CSN=0). For start up time see Table 13. The power down is controlled by
the PWR_UP bit in the CONFIG register.