Mission_ACK Datapacket

[Ahmet Basri Altay]

Hi everyone, 

Mission_ACK message message looks like above. But when i read the communication channel i see a message like below.

In this message, 2f 00 00 message id, ff be payload, and the other two bytes are crc values. What do these two bytes mean in this case? Who gives the type value of Ack?

Can you help me? please.. 

[Hamish Willee]

CRC value is CRC run over the message values, in over-the wire order, then with a CRC EXTRA accumulated on top. The CRC extra is a definition of this message format (i.e. it is a CRC run over the message definition including the name of the mission, and the names/types of each of the fields).
On receiving a message you can run the CRC on the received data and then apply the CRC extra. If the resulting number matches the value you see above, then you would know that the message had not been corrupted in transit AND that the receiver has the same understanding of the message definition as the sender.

Info on this in https://mavlink.io/en/guide/serialization.html#crc_extra

[Ahmet Basri Altay]

I understand but my problem is not with CRC. The message you see in the photo is a message from autopilot. I want to read the payload of the message. The payload on the site is 3 bytes, but the message I received is 2 bytes. What byte is missing and why it is missing is what I can't figure out.

Hamish Willee <hamish...@gmail.com>, 29 Eyl 2022 Per, 04:03 tarihinde şunu yazdı:

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[Hamish Willee]

I have no idea. I assume since you say "3 bytes" you're sending mavlink 1? If MAVLink 2 I would inspect using wireshark https://mavlink.io/en/guide/wireshark.html

Sorry I can't be more help. 

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[Ahmet Basri Altay]

As you can see here, this is a mavlink2 message. I don't know if you'll see anything different in Wirehawk. But I would be very happy if you could take a look. I used serial port monitor.

Hamish Willee <hamish...@gmail.com>, 29 Eyl 2022 Per, 10:37 tarihinde şunu yazdı:

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[Hamish Willee]

Are the values you are sending for type or mission_type equal to zero? If so, and you are just looking at "over the wire data" then what you are seeing is zero byte payload truncation: https://mavlink.io/en/guide/serialization.html#payload_truncation

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[Ahmet Basri Altay]

Ohh, I got it now. Thank you very much. This was very helpful..

Hamish Willee <hamish...@gmail.com>, 29 Eyl 2022 Per, 10:55 tarihinde şunu yazdı:

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