JN517X Datasheet, PDF (31/100 Pages) NXP Semiconductors – Supports multiple network stacks

NXP Semiconductors
JN517x
IEEE802.15.4 Wireless Microcontroller
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9.7.3.1 Transmit
A transmission is performed by software writing the data to be transferred into the TX
frame buffer in RAM, together with parameters such as the destination address and the
number of retries allowed, as well as 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 the 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, fetching
the packet data directly from RAM. It can perform all the algorithms required by
IEEE802.15.4 such as CSMA/CA without processor intervention, including retries and
random back-offs.
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
serializer 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.
9.7.3.2 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 receive frame buffer in RAM where both
header and frame data can be read by the protocol software. An interrupt may be provided
on receipt of the frame. An additional interrupt may be provided after the transmission of
an acknowledgement frame in response to the received frame, if an acknowledgement
frame has been requested and the auto acknowledge mechanism is enabled, see
Section 9.7.3.3. 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
JN517X
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 2.0 — 8 November 2016
© NXP Semiconductors N.V. 2016. All rights reserved.
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