nRF24LE1 Nordic VLSI, nRF24LE1 Datasheet - Page 24

• Manufacturer Part Number: nRF24LE1
• Manufacturer: Nordic VLSI

nRF24LE1 Preliminary Product Specification
3.4.3.3
Figure 8.
The packet control field contains a 6 bit payload length field, a 2 bit PID (Packet Identity) field and a 1 bit
NO_ACK flag.
Payload length
This 6 bit field specifies the length of the payload in bytes. The length of the payload can be from 0 to 32
bytes.
Coding: 000000 = 0 byte (only used in empty ACK packets.) 100000 = 32 byte, 100001 = Don’t care.
This field is only used if the Dynamic Payload Length function is enabled.
PID (Packet identification)
The 2 bit PID field is used to detect if the received packet is new or retransmitted. PID prevents the PRX
operation from presenting the same payload more than once to the MCU. The PID field is incremented at
the TX side for each new packet received through the SPI. The PID and CRC fields (see
page
data packets are lost on the link, the PID fields may become equal to the last received PID. If a packet has
the same PID as the previous packet, the RF Transceiver compares the CRC sums from both packets. If
the CRC sums are also equal, the last received packet is considered a copy of the previously received
packet and discarded.
No Acknowledgment flag (NO_ACK)
The Selective Auto Acknowledgement feature controls the NO_ACK flag.
This flag is only used when the auto acknowledgement feature is used. Setting the flag high, tells the
receiver that the packet is not to be auto acknowledged.
3.4.3.4
The payload is the user defined content of the packet. It can be 0 to 32 bytes wide and is transmitted on-air
when it is uploaded (unmodified) to the device.
Enhanced ShockBurst™ provides two alternatives for handling payload lengths; static and dynamic.
The default is static payload length. With static payload length all packets between a transmitter and a
receiver have the same length. Static payload length is set by the RX_PW_Px registers on the receiver side.
The payload length on the transmitter side is set by the number of bytes clocked into the TX_FIFO and
must equal the value in the RX_PW_Px register on the receiver side.
Revision 1.1
25) are used by the PRX operation to determine if a packet is retransmitted or new. When several
shows the format of the 9 bit packet control field, MSB to the left.
Packet Control Field
Payload
Payload length 6bit
Figure 8. Packet control field
24 of 191
PID 2bit
NO_ACK 1bit
section 3.4.3.5 on