UCD3138: UCD3138/UCD3138A CLA AND EVENT UPDATE WINDOW

jun yin

Part Number: UCD3138

Hi Sir:

I have two questions; we try to use EVENT_UP_SEL=0,Events updated anytime for DPWM normal mode so we try to avoid the event update during DPWM edges;

1\ what's the CLA delay between SAMPTRIG and Filter Output?

2\are DPWM edges including EV1,EV2,EV3,EV4?for "If DPWM edges move in or out of the Event Update Window, those transitions
may be missed, leading to DPWM pulses longer or shorter than expected."

thanks a lot;

over 7 years ago

0 jun yin over 7 years ago

Intellectual 875 points

for UCD3138 and UCD3138A; thanks a lot;

0 Yitzhak Bolurian over 7 years ago in reply to jun yin

TI__Mastermind 18370 points

In normal mode the moving edges are only EV2 and EV3 and those are the edges that should not go inside the event update window. EV1 and EV4 do not matter.

The delay for the CLA is about 450 nS.

For UCD3138 the event update window is by default 75 nS from the start of period.

For UCD3138A the event update window is by default 135 nS from the start of period.

UCD also offers an option to move the EUW (event update window) away from the begging of period (by EVENT_UP_SEL set to 2 or 3) .

In this case the position of EUW is determined by sample trigger 2 positioning.

0 jun yin over 7 years ago in reply to Yitzhak Bolurian

Intellectual 875 points

Hi Sir:
if we adjust EV1 and EV4 in standard interrupt to adjust dead time dynamically, that makes EV1 EV4 moving edge also, right?
thanks a lot;

0 Yitzhak Bolurian over 7 years ago in reply to jun yin

TI__Mastermind 18370 points

By moving edges, we mean the edges that move by folter update.
If EV1 and Ev4 move by firmware, that is fine. EV1 and EV4 are not considered moving edges in this sense.

0 jun yin over 6 years ago in reply to Yitzhak Bolurian

Intellectual 875 points

Hi Sir:
I just checked that we're using DPWM0 in multi mode;
could we use it in below way for DPWM0?
1\set SAMPLE_TRIG_1 and use its over sampling of 2 samples;
2\set EVENT_UP_SEL as 3 : At both End of Period and at time set by sample trigger 2
3\set SAMPLE_TRIG_2 as PERIOD/2
4\set SAMPLE_TRIG_2_EN 0 to disable TRIG_2's sample trigger!!!
so we could do event update at the end of period of DPWM0 and at PERIOD/2 of DPWM0 without triggering CLA at SAMPLE_TRIG_2?
THANKS A LOT

0 Yitzhak Bolurian over 6 years ago in reply to jun yin

TI__Mastermind 18370 points

It is not easy to answer this question without knowing the exact timmings of all these events.
I have never tried this configuration.
You should make sure that:
1) No moving edges in both EUWs (Event update windows).
2) The interval between the samples and between the last sample and EUW is greater than 500 nS.

0 Yitzhak Bolurian over 6 years ago in reply to Yitzhak Bolurian

TI__Mastermind 18370 points

Hi Jun, if this addressed your question, please set the state of this thread as resolved.
Thanks and regards,

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UCD3138: UCD3138/UCD3138A CLA AND EVENT UPDATE WINDOW