Linx Technologies TRM-915-R250 - Manual (Page 12)

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Extended User Addressing Mode
Extended User Networking Mode is the same as User Networking Mode
but uses longer addresses. The two customer ID bytes are still used
(regCUSTID[0-1]) but all four bytes are used for the user destination
address (regUSERDESTID[0-3]), user source ID (regUSERSRCID[0-3])
and user ID mask (regUSERIDMASK[0-3]). This provides more addressing
capabilities at the expense of more overhead in the packet. Otherwise all
functionality is the same.
250 Series Transceiver Extended User Network Mode Examples
Sender Receiver
Network
Mode
User
SRCID
User
DESTID
User
SRCID
User
IDMASK
Response
0x07 0x10000000 0xFFFFFFFF
0x20000001 0XFFFFFFFF Data output by
both modules. No
ACK sent by either
module.
0x20000002 0xFFFFFFFF
0x17 0x10000000 0xFFFFFFFF
0x20000001 0xFFFFFFFF Data output by
both modules.
No ACK sent by
either module. This
configuration will
cause transmission
problems.
0x20000002 0xFFFFFFFF
0x17 0x10000000 0x30000001
0x20000001 0xE0000000 Data output. No
ACK sent.
0x30000001 0xE0000000 Data output. ACK
sent to 0x1000.
0x07 0x10000000 0x30000002
0x20000001 0xF0000000 Not processed –
discarded.
0x30000001 0xF0000000 Data output. No
ACK sent.
250 Series Transceiver User Network Mode Examples
Destination
ID from
Received
Packet
Receiver
Source
ID
Receiver
User ID
Mask
Result of
Dest
AND
Mask
Result of
Source
AND
Mask
Action
1234
Any
module
with
123x
FFF0 1230 1230
The results are equal, so
the payload is output on
the UART.
Do not enable
acknowledgements
Figure 14: 250 Series Transceiver User Network Mode Examples
Figure 15: 250 Series Transceiver Extended User Network Mode Examples
Assured Delivery (Acknowledgement)
While not an addressing mode on its own, assured delivery can be
enabled for each of the addressing modes. When a module transmits
with assured delivery enabled, it obligates the receiving module to return
an acknowledgement packet. The transmitting module waits for this
acknowledgement for a preset amount of time based on the data rate.
If an acknowledgement is not received, it retransmits the packet. If the
receiver receives more than one of the same packet, it discards the packet
contents but sends an acknowledgment. This way, duplicate data is not
output by the module. It is extremely important that assured delivery be
used only when the unmasked user/extended user Destination ID or
Destination GUID points to a specific module. Failure to specifically address
a valid module could cause the module to appear slow or unresponsive
due to repeated retransmissions. This also serves to congest the network,
impeding valid communications.
If the received destination address matches the local address, the receiving
module immediately sends an RF ACK packet. This packet lets the sending
module know that the message has been received. An RF ACK packet is
sent immediately following reception; CSMA delay is not applied to RF ACK
packets. When the sending module receives the RF ACK packet, it marks
the current block of data as completed. If this is the last message in the
queue, the sending module asserts the BE line to indicate the state of the
incoming buffer.
Troubleshooting Hint: If modules are unable to communicate with each
other, check the following:
• Check to make sure that both modules are set to the same data rate.
Modules programmed with different data rates will not communicate or
share an RF channel with one another.
• Ensure that the network mode and addressing is configured to properly
access the module of interest. Also, ensure that a specific module is
addressed when using acknowledgment. Failure to do so causes large
delays and loss of data.