DMR ID (LC) display delay

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VK3KYY
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Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: DMR ID (LC) display delay

Post by VK3KYY » Sat Jul 29, 2023 9:03 pm

netdog wrote:
Sat Jul 29, 2023 8:44 pm
Hi,

I noticed that DMR IDs are displayed with a delay. I may not know all the nuances, but playing with debugging, I made sure that the DMR ID (FullLC pdu), is updated with the arrival of the VoiceF (seq=6) frame (if the CRC is correct), it is embedded in the entire superframe.
A Also even earlier it is available by Voice LC Header at the same address, it can be defined as rxSyncClass == SYNC_CLASS_DATA && rxDataType == 1 .

This would help to avoid unnecessary delays in the output of information.

I tried listening to a BS that has RAS (modified crc), and it looks like the HR_C6000 doesn't update the EmbeddedLC data if the CRC was wrong. I have not yet understood how you can ignore this or at least find out if there is a crc error there.
The C0000 decodes the DMR frames, and from what I remember the detection is unreliable, so we have to wait for multiple frames with the same data before we know that the data is correct, hence why the data is not displayed immediately

Originally we displayed the data instantly , but people complained that sometimes the wrong data was initially displayed, and this data goes into the Last Heard etc

I don't think the C6000 implements the CRC checking correctly, because the CRC seems to be always reported as valid, even then the data is completely wrong

Like most things in these cheap radios, things don't work as well as in radios with better hardware e.g. Motorola and Anytone etc

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