2008-01-20 23:00:53     Questions about the PPI with 1 frame sync

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2008-01-20 23:00:53     Questions about the PPI with 1 frame sync

kick game (CHINA)

Message: 49873   

 

Dear all,

 

I want to transfer datas between two Blackfin CPUs using the PPI directly.. Did someone do the same working before? Please give me some advices to how to config the PPI properly..

 

Now I config both of them working with 1 frame sync..One is the master and the other is the slave. The master's PPI worked with the TX mode, 1 internal frame sync with the PPI_CONTROL register is

 

PORT_EN | PORT_DIR | XFR_TYPE | PACK_EN | DLEN_8 (my DMA is 16 bits and PPI is 8 bits)

 

and the PPI_FS1 got by the timer8 with CLK_SEL and TIN_SEL setted.

 

The slave's PPI_CONTROL register is PORT_EN | XFR_TYPE | PACK_EN | DLEN_8...

 

I found it's very difficult to synchronize the data between the master and the slave. I have two questions now:

 

1. The datasheet said "the PPI does not start data transfer after being enabled until the appropriate synchronization

signals are received".  But I found that it will work as soon as the PPI is enable even thought there isn't any synchronization signals. Maybe My configuration is wrong?(PPI_DELAY=0(master) or 1(slave), both of PPI_COUNT is same );

 

2. In this mode, PPI_FS3 should pull to ground? I think it's not needed.

 

Now the master always send out wrong data with all zeros(of cources it  actually isn't). The Master's another PPI(PPI1 of bf561) is using by the MPEG4  algorithm.. Maybe the bandwidth is not enough? My PPI_CLK is about 5MHz.

 

Thanks a lot! Any clue is appreciated..

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2008-01-20 23:39:04     Re: Questions about the PPI with 1 frame sync

Robin Getz (UNITED STATES)

Message: 49874    kick:

 

Are you using Linux in this? Which PPI driver are you trying to use?

 

Thanks

-Robin

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2008-01-20 23:57:39     回复: Re: Questions about the PPI with 1 frame sync

kick game (CHINA)

Message: 49875   

 

Dear Robin:

 

       I'm using PPI0..The master runnig the MPEG4 is on VDSP and the slave is uClinux..

 

Thanks a lot..

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2008-01-21 14:57:29     Re: Questions about the PPI with 1 frame sync

Michael Hennerich (GERMANY)

Message: 49894   

 

Check PPI_CONTROL POL_S and POL_C bits.

 

-Michael

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