Downlink and Uplink over SPI in bridge mode

Wireless Connectivity Ultra-Wideband
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Hello

Reading all the docs available and searching in this forum I know that the uplink and downlink messages are done with the dwm_backhaul_xfer (pg 93 of Firmware guide pdf) spi function.

The main question is how the data is structured in that messagens, both uplink and downlink. (e.g.) What I have to write in downlink sequece to change the update rate of a specific tag?

There are a lot of similar unanswered posts in this forum. My hope is that someone who recently made some reverse engineering on RPI+DWM communication could share his/her findings.

Since there is no official documentation how to properly use this function, is there any chance of Decawave/Qorvo releasing some of these information? Or since leapslabs has now its own solutions, no update will be released? At least for now.

Best Regards,
Felipe Arnhold

2

Hi Arnold,

I’m sorry but this is not part of the documentation and it is not supported for now.

Sending the downlink is quite a complex task, encoding of uplink and downlink is not enough, there are other things that are needed to deliver the downlink to the node in the UWB network, you need to send the downlink at exact time and place it in exact seat etc. in order to reach the node successfuly. For that you need to tract all the nodes in the networks and keep information about them etc.

JF

1 Like
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Hi leapslabs

This makes total sense. Thank you for the explanation.

Best Regards,
Arnhold

4

Hi leapslabs,

I made modifications on the user application part of the tags’ firmware and now tags are capable of reading and processing downlink iot data, thanks to USER_DATA_EVENT interrupts. Therefore, I need to regularly send downlink data to the tags. There are some questions about this:

  • How can I make sure that my iot data message is received from the tag? Can there be missed packets?

  • In a large network with multiple bridge nodes (assume 3 gateways, one is proxy-server host, as in DWM1001 Gateway Quick Deployment Guide, Figure 15), who delivers the downlink data to the tag connected with the bridge node G3? And to which broker address and port the downlink data should be sent for this tag?

Thanks in advance.

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Hi @nevinsehbal
see my answers below:

  • How can I make sure that my iot data message is received from the tag? Can there be missed packets?

There is no mechanism that guarantee you the message delivery so the message could get lost during UWB transmission.

  • In a large network with multiple bridge nodes (assume 3 gateways, one is proxy-server host, as in DWM1001 Gateway Quick Deployment Guide, Figure 15), who delivers the downlink data to the tag connected with the bridge node G3? And to which broker address and port the downlink data should be sent for this tag?

This is done automatically in GW firmware. Each GW track its available nodes and publish/subscribe to the node topics. So then downlink occurs the GW who has the node in range grab the downlink message and forward it to the desired node.

Cheers
JK