Product Specs

Table Of Contents
23 RADIO 2.4 GHz Radio
Page
205
RAM
RADIO
Packet synch
ANT1
MAXLEN
Payload
S1
Whitening
CRC
L
2.4 GHz
Transmitter
S0
Packet
assembler
IFS
control unit
Bit counter
Payload
S1
L
S0
Dewhitening
CRC
EasyDMA
2.4 GHz
Receiver
Packet
disassembler
RSSI
Address
match
Device
Address
match
PACKETPTR
23 RADIO 2.4 GHz Radio
The RADIO contains a 2.4 GHz radio receiver and a 2.4 GHz radio transmitter that is compatible with
Nordic's proprietary 1 Mbps and 2 Mbps radio modes in addition to 1 Mbps and 2 Mbps Bluetooth
®
low
energy mode.
EasyDMA in combination with an automated packet assembler and packet disassembler, and an automated
CRC generator and CRC checker, makes it very easy to configure and use the RADIO. See Figure 29:
RADIO block diagram on page 205 for details.
Figure 29: RADIO block diagram
The RADIO includes a Device Address Match unit and an interframe spacing control unit that can be
utilized to simplify address white listing and interframe spacing respectively, in Bluetooth Smart and similar
applications.
The RADIO also includes a Received Signal Strength Indicator (RSSI) and a bit counter. The bit counter
generates events when a preconfigured number of bits have been sent or received by the RADIO.
23.1 EasyDMA
The RADIO use EasyDMA for reading and writing of data packets from and to the RAM without CPU
involvement.
As illustrated in Figure 29: RADIO block diagram on page 205, the RADIO's EasyDMA utilizes the same
PACKETPTR for receiving and transmitting packets. The CPU should reconfigure this pointer every time
before the RADIO is started via the START task.
The structure of a radio packet is described in detail in Packet configuration on page 206. The data that
is stored in Data RAM and transported by EasyDMA consists of S0, LENGTH, S1, the payload itself, and a
static add-on sent immediately after the payload.
The size of each of the above elements in the frame is configurable (see Packet configuration on page
206), and the space occupied in RAM depends on these settings. A size of zero is possible for any of the
fields, it is up to the user to make sure that the resulting frame complies with the RF protocol chosen.
For the field sizes defined in bits, the occupation in RAM will always be rounded up to the next full byte size
(for instance 3 bit length will allocate 1 byte in RAM, 9 bit length will allocate 2 bytes, etc.).