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ADV212 behavior under backpressure

Question asked by Sergey_Svoysky on Feb 24, 2015
Latest reply on Feb 24, 2015 by DaveD

 

We are sending video frames to ADV212 over the 16 bit HBUS (single component for encoding).

We finish receiving a burst from ADV and then stop activating the DACK1 to test backpressure.

(The ADV is activating DREQ).

We are backpressuring the ADV by not ACKing.

After a few seconds we resume ACKing on the HBUS and the ADV seems to resume normal operation.

However after some short time it stops generating DREQs to get uncompressed data and then stops generating DREQs to send out compressed data.

After we stop the ACKs the register read is as follows:

Reading ADV-0 at address 4100C800 0: 0xC910

Reading ADV-0 at address 4100C804 1: 0xC910

Reading ADV-0 at address 4100C808 2: 0xC910

Reading ADV-0 at address 4100C80C 3: 0xC910

Reading ADV-0 at address 4100C810 4: 0xC910

Reading ADV-0 at address 4100C814 5: 0x 400

Reading ADV-0 at address 4100C818 6: 0x44EF

Reading ADV-0 at address 4100C81C 7: 0xCCCC        <-------  SWFLAG

Reading ADV-0 at address 4100C820 8: 0x   5

Reading ADV-0 at address 4100C824 9: 0x   5

Reading ADV-0 at address 4100C828 A: 0x1412

Reading ADV-0 at address 4100C82C B: 0xFFFF

Reading ADV-0 at address 4100C830 C: 0x   0

Reading ADV-0 at address 4100C834 D: 0x   D

Reading ADV-0 at address 4100C838 E: 0x  88

Reading ADV-0 at address 4100C83C F: 0x   4

 

 

What does SWFLAG=0xCCCC mean?

Can ADV212 operate under backpressure or we must always provide the ACK when it wants to send us data?

 

Thanks, sergey

 

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