NXP Semiconductors MKW01Z128, Справочное руководство

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Transceiver Digital Control and Communications
MKW01xxRM Reference Manual, Rev. 3, 04/2016
7-16 Freescale Semiconductor, Inc.
Every received packet which does not start with this locally configured Sync word is automatically
discarded and no interrupt is generated.
When the Sync word is detected, payload reception automatically starts and SyncAddressMatch is asserted.
NOTE
Sync Word values containing 0x00 byte(s) are forbidden.
7.5.7.2 Address Based
Address filtering can be enabled via the AddressFiltering bits. It adds another level of filtering, above Sync
word (i.e. Sync must match first), typically useful in a multi-node networks where a network ID is shared
between all nodes (Sync word) and each node has its own ID (address).
Two address based filtering options are available:
• AddressFiltering = 01 : Received address field is compared with internal register NodeAddress . If
they match then the packet is accepted and processed, otherwise it is discarded.
• AddressFiltering = 10 : Received address field is compared with internal registers NodeAddress
and BroadcastAddress . If either is a match, the received packet is accepted and processed,
otherwise it is discarded. This additional check with a constant is useful for implementing
broadcast in a multi-node networks
Please note that the received address byte, as part of the payload, is not stripped off the packet and is made
available in the FIFO. In addition,
NodeAddress and AddressFiltering only apply to RX. On TX side, if
address filtering is expected, the address byte should simply be put into the FIFO like any other byte of the
payload.
As address filtering requires a Sync word match, both features share the same interrupt flag
SyncAddressMatch .
7.5.7.3 Length Based
In variable length Packet mode, PayloadLength must be programmed with the maximum payload length
permitted. If received length byte is smaller than this maximum then the packet is accepted and processed,
otherwise it is discarded.
Please note that the received length byte, as part of the payload, is not stripped off the packet and is made
available in the FIFO.
To disable this function the user should set the value of the PayloadLength to 255.
7.5.7.4 CRC Based
The CRC check is enabled by setting bit CrcOn in RegPacketConfig1 . It is used for checking the integrity
of the message.
• On TX side a two byte CRC checksum is calculated on the payload part of the packet and appended
to the end of the message