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Link Port synchronisation issue

Question asked by ChristianH on Sep 14, 2016
Latest reply on Sep 22, 2016 by ChristianH

Hi,

 

I'm using 2 ADSP-21469 DSPs.

First DSP receives data on SPORTs and transmits data on Link Port 0.

Second receives data on Link Port 1 and transmits data on SPORTs.

Audio data synchronisation and buffering is done with SPORT IRQ.

 

I've also enabled Link Port DMA interrupt to disable the Link Ports once the transfers are finished.

In the interrupt service I'm reading LSTATx and clearing LCTLx to disable the Link Port.

Inside the SPORT interrupt service I'm enabling the Link Ports again.

 

My problem is that even if I disable the receiving Link Port the LACK line stays high (external 27k pull-down).

So the transmitting Link Port sends the first data although the receiving one is not enabled.

On the EZKIT I see 10k pull-down resistors, so if I connect 2 boards I have a remaining 5k resistance.

But HWR page 5-7 states a 20k pull-down.

 

Can anyone help me here?

 

Regards

Christian

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