Custom Serial Decoders?

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GraveDigger

Custom Serial Decoders?

Post by GraveDigger »

Hi,

I just wanted to know, if there is a way to add protocols for the serial decoder. I'd like to have a decoder for the AC97 Serial Link Protocol within picoscope. This would come in really handy since a AC97 (rev 2.1) protocol frame is 256 * 81.38 picoseconds long. I am using a 3204B picoscope.

ziko
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Re: Custom Serial Decoders?

Post by ziko »

Hi I am not following what is this protocol ? You say 256*81.38 picoseconds long, that seems very quick. What is the AC97 serial protocol? Do you mean for the audio chip?

Kind regards
Ziko

Technical Specialist

GraveDigger

Re: Custom Serial Decoders?

Post by GraveDigger »

Hi Ziko,

yes indeed, it's for those ac97 codec chips. In my case i am developing an AC97 Controller (FPGA based) for an national LM4550 Codec IC, datasheet is here: http://www.national.com/ds/LM/LM4550.pdf
The AC97 Serial Link Protocol is described starting at page 18. I mistyped the clock value tho, it's not 81.39 picoseconds but 81.39 nanoseconds, sorry for that.

In short, this protocol packs data in frames of 256 bits length, the frame is divided in 13 so called "slots", the first one 16 bits wide, all other 20 bits. Each bit is clocked at the rising edge of the bit clock from one IC and sampled on the falling edge within the other IC. A Sync signal marks the beginning of a frame. So it's pretty straight forward and should not be that hard to implement.

The Question remains tho, can i add a decoder for this protocol to the picoscope software somehow?

ziko
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Posts: 1705
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Re: Custom Serial Decoders?

Post by ziko »

Hi as it stands the software does not support this, however I have forwarded your suggestion to the relevant department.

Kind regards
Ziko

Technical Specialist

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