JN5148-001-X NXP Semiconductors, JN5148-001-X Datasheet - Page 30

• Manufacturer Part Number: JN5148-001-X
• Description: IC MCU 802.15.4 32BIT 2.4G 56QFN
• Manufacturer: NXP Semiconductors
• Series: JN5148r

Specifications of JN5148-001-X

• Frequency: 2.4GHz
• Data Rate - Maximum: 667kbps
• Modulation Or Protocol: 802.15.4
• Applications: Home/Building Automation, Industrial Control
• Power - Output: 2.5dBm
• Sensitivity: -95dBm
• Voltage - Supply: 2 V ~ 3.6 V
• Current - Receiving: 17.5mA
• Current - Transmitting: 15mA
• Data Interface: PCB, Surface Mount
• Memory Size: 128kB RAM, 128kB ROM
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 56-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 616-1049-2; 935293999531; JN5148-001-X

8.3 Baseband Processor
The baseband processor provides all time-critical functions of the IEEE802.15.4 MAC layer. Dedicated hardware
guarantees air interface timing is precise. The MAC layer hardware/software partitioning, enables software to
implement the sequencing of events required by the protocol and to schedule timed events with millisecond
resolution, and the hardware to implement specific events with microsecond timing resolution. The protocol software
layer performs the higher-layer aspects of the protocol, sending management and data messages between endpoint
and coordinator nodes, using the services provided by the baseband processor.
8.3.1 Transmit
A transmission is performed by software writing the data to be transferred into the Tx/Rx Frame Buffer, together with
parameters such as the destination address and the number of retries allowed, and programming one of the protocol
timers to indicate the time at which the frame is to be sent. This time will be determined by the software tracking the
higher-layer aspects of the protocol such as superframe timing and slot boundaries. Once the packet is prepared and
protocol timer set, the supervisor block controls the transmission. When the scheduled time arrives, the supervisor
controls the sequencing of the radio and modem to perform the type of transmission required. It can perform all the
algorithms required by IEEE802.15.4 such as CSMA/CA, GTS without processor intervention including retries and
random backoffs.
When the transmission begins, the header of the frame is constructed from the parameters programmed by the
software and sent with the frame data through the serialiser to the Modem. At the same time, the radio is prepared
for transmission. During the passage of the bitstream to the modem, it passes through a CRC checksum generator
that calculates the checksum on-the-fly, and appends it to the end of the frame.
If using slotted access, it is possible for a transmission to overrun the time in its allocated slot; the Baseband
Processor handles this situation autonomously and notifies the protocol software via interrupt, rather than requiring it
to handle the overrun explicitly.
8.3.2 Reception
During reception, the radio is set to receive on a particular channel. On receipt of data from the modem, the frame is
directed into the Tx/Rx Frame Buffer where both header and frame data can be read by the protocol software. An
interrupt may be provided on receipt of the frame header. As the frame data is being received from the modem it is
passed through a checksum generator; at the end of the reception the checksum result is compared with the
checksum at the end of the message to ensure that the data has been received correctly. An interrupt may be
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Bitstream
Bitstream
Radio
Rx
Tx
Checksum
Checksum
CSMA
Append
Verify
Protocol Timing Engine
Supervisor
CCA
Control
Status
Deserialiser
Serialiser
Backoff
Control
Figure 20: Baseband Processor
JN-DS-JN5148-001 1v6
Security Coprocessor
Codec
AES
Encrypt
Decrypt
Port
Port
© NXP Laboratories UK 2010
Protocol
Timers
Frame
Tx/Rx
Buffer
Processor
Bus