NRF2401A Datasheet, PDF (23/38 Pages) List of Unclassifed Manufacturers – Single chip 2.4 GHz Transceiver

PRODUCT SPECIFICATION
nRF2401A Single Chip 2.4 GHz Radio Transceiver
DATA PACKAGE DESCRIPTION
PRE-AMBLE ADDRESS
PAYLOAD
Figure 11 Data Package Diagram
CRC
The data packet for both ShockBurst™ mode and direct mode communication is
divided into 4 sections. These are:
1. PREAMBLE
2 ADDRESS
3 PAYLOAD
4 CRC
• The preamble field is required in ShockBurst™ and Direct modes.
• Preamble is 8 bits in length and is dependent of the first data bit in direct
mode.
PREAMBLE
1^st ADDR-BIT
01010101
0
10101010
1
• Preamble is automatically added to the data packet in ShockBurst™ and
thereby gives extra space for payload. In Direct mode MCU must handle
preamble.
In ShockBurst™ mode RX, the preamble is removed from the received output
data, in direct mode the preamble is transparent to the output data.
• The address field is required in ShockBurst™ mode.¹
• 8 to 40 bits length.
• Address automatically removed from received packet in ShockBurst™
mode. In Direct mode MCU must handle address.
• The data to be transmitted
• In ShockBurst™ mode payload size is 256 bits minus the following:
(Address: 8 to 40 bits. + CRC 8 or 16 bits).
• In Direct mode the maximum packet size (length) is for 1Mbps 4000 bits
(4ms).
• The CRC is optional in ShockBurst™ mode, and is not used in Direct
mode.
• 8 or 16 bits length
• The CRC is removed from the received output data in ShockBurst™ RX.
Table 18 Data package description
1 _{Suggestions for the use of addresses in ShockBurst™: In general more bits in the address gives less}
false detection, which in the end may give lower data packet loss.
A. The address made by (5, 4, 3, or 2) equal bytes are not recommended because it in general will
make the packet-error-rate increase.
B. Addresses where the level shift only one time (i.e. 000FFFFFFF) could often be detected in noise
that may give a false detection, which again may give raised packet-error-rate.
Direct mode will be dependent on the software used in the MCU, but it is recommended to have the
same restrictions on addresses for this mode.
Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0
Page 23 of 38
December 2004