Need help with Lua, RS232, Hex, checksum, recieve values

[Wernicke]

Hi
I'm trying to control my reciever(NAD T763) by RS232.
After monitoring the serial interface while using the dedicated NAD control application I've been able to document the commands I need. I've been able to utilize this commands via the Transport Send funcions, and the included SimpleSendAndRecieve-lua script.

However, I want more
1: I want to query values, like volume, source etc
2: I want these values available on the girder webpage
Here's where I need help. I don't know what to add to the lua file, the rs232-documentation is a lot more advanced that I'm used to, and I don't know how to present these values in the web page.

My forum user is not allowed to add url's to the RS232-documentation, but I'll try to explain:
Basicly the format is like this: <start>, Command, Data, <checksum>, 8-bit Checksum
Where <start> is always 01, <checksum> is always 02, and the 8-bit Checksum is ones complement of the sum of the Command and Data bytes.
Also note that values 0-19 is reserved, and need to be encoded with a flag character of 94

Set examples:
01 16 C2 02 27 - Set Source 1
01 16 C0 02 29 - Set Source 2
01 16 8C 02 5D - Set Volume -1 dB
01 16 88 02 61 - Set Volume +1 dB
Query examples: HEX14(DEC20)=Query
01 14 14 02 D7 Answer:01 14 14 54 37 36 33 02 E3

Best Regards, Sigurd

[Tieske8]

Whats the exact question?

[Wernicke]

Need help modifying the simple lua file to receive answer to queries. Right now I'm just sending values to change volume etc. I will also need to calculate checksums as well, but my first priority is to actually receive a value, and present it in girder.
So first things first.
I want to send "01 14 14 02 D7", the receiver will reply with "01 14 14 54 37 36 33 02 E3"(1,20,20,84,55,54,51,2), where 84,55,54,51=T763. I want to display T763 on screen.

Best Regards, Sigurd

[Wernicke]

And I guess the first question is: What should I define as the the terminator character?

[Tieske8]

And I guess the first question is: What should I define as the the terminator character?

From the example you gave I have the impression that its not a terminated protocol, but a fixed length protocol (every message/response has the same number of bytes).

[Tieske8]

Need help modifying the simple lua file to receive answer to queries. Right now I'm just sending values to change volume etc. I will also need to calculate checksums as well, but my first priority is to actually receive a value, and present it in girder.
So first things first.
I want to send "01 14 14 02 D7", the receiver will reply with "01 14 14 54 37 36 33 02 E3"(1,20,20,84,55,54,51,2), where 84,55,54,51=T763. I want to display T763 on screen.

Best Regards, Sigurd

What is "the simple lua file", what code are you currently using? and displaying; on what screen?

[Wernicke]

SimpleSendAndReceive.lua in the transport/devices folder.
By displaying I meant OSD, but receiving a reply in the log is sufficient.

[Wernicke]

Looks to me that it can be different lenght.
01 15 39 5E 41 02 B0 = Radio preset 1
01 16 CE 02 1B = Speaker A On/Off

Is it possible to define the termiator as HEX 02 + one byte?