CYRF9935

Document Number: 001-88748 Rev. *G

Page 13 of 47

Packet Control Word

Packet Control Word is a 10 bit field which is automatically attached to the transmitting packet and removed from the received packet

by the radio’s baseband engine.

Payload Length

Payload length is a 6 bit field which is attached if DPL is 1 (refer Register Sets on page 26). It represents the payload length for the

data packet. A value of 000000 means 0 byte data payload is carried while a value of 000001 means 1 bytes data payload are carried

and so on (values in excess of 100000 are not valid).

PID

The PID is a 3-bit value that ranges from 1~7 and is incremented by 1 for every new packet. For every packet received, if the PID is

same as last packet and computed CRC is not same as the previous packet, it is assumed a new packet is received. If both the PID

and CRC for the received packet is same as the previous packet then the current packet is assumed to be a re-transmission of the

previous packet. PID is always 0 for Auto-ACK packet.

NOACK

The NOACK is a 1 bit field which is inserted to the transmitted packet if DPL is enabled (refer Register Sets on page 26). If NOACK

is set to 0 then an ACK packet will be exchanged between the receiver and the transmitter, if an error free payload packet was

transmitted. For an Auto-ACK packet or broadcast packet the NOACK is set to 1.

Data Payload

Length is programmable 0 to 32 bytes.

CRC

CRC is an error detection mechanism provided to validate the data correctness of a received packet. CRC length is programmable

to be either 1 or 2 bytes long. The CRC value is calculated over the packet control word and payload. The CRC is automatically

calculated and appended to the transmitted packet. On the receiver side the CRC is removed from the received packet by the

baseband engine. The received packet will be ignored if CRC mismatch happens. The number of bytes in CRC field is set by CRCLNG

bit in direct register 0x03 (refer to Register Sets on page 26).

Broadcast Address

CYRF9935 can transmit and receive broadcast packets. The bit-field BCEN must be set to enable the function for a RXer. To transmit

a broadcast packet, W_TX_PAYLOAD SPI command is used and the TX Pipe Number in the command is set with 0 to indicate this

is a broadcast packet. You can use R_RX_PAYLOAD SPI command to receive the broadcast packet if RX Pipe Number in the

command is set to 0. The broadcast address is 0xE7, 0x39, 0xCE, 0x73, 0x9C depending on the address length (ADDRLNG register)

setting. The address must be reserved for the broadcast use. In a broadcast packet, both Destination Pipe Address and Source Pipe

Address are not attached.

Table 15. Packet Control Word Format

Payload Length

PID

NOACK

6 bits

3 bits

1 bit

Table 16. Registers Table for Broadcast Enable

Address (Hex)

Mnemonic

Bits

Init

RW

Description

0x23

BCEN

0

0

R/W

Broadcasting Listening Enable

0: Broadcasting packets are ignored.

1: Broadcasting packet can be received.