Hi Vinod,
By changing the preset, you change either pre, post or main taps of the
driver. All three taps responsible for constructing a particular amplitude.
Amplitude register should account for the amplitude level when Tx
equalizing is not set, i.e preset 4.
Boris Bakshan.
On Apr 28, 2015 06:59, "vinod ah" <ah.vinod@xxxxxxxxx> wrote:
Hi All,
In PCIe3 Tx electricals, I see that by changing the presets, there is
change in waveform amplitude.
For example, in compliance testing of Tx, P4 has highest amplitude (Vpp)
and P7 has the lowest Vpp.
But amplitude control register is still at same setting. So trying to
understand, why is there a change in amplitude (Vpp) as preset is just a
pre-post cursor setting and not related to amplitude (if i am not wrong
here as i am unaware of Tx driver designs).
Regards
Vinod A H
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