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Pin Buffer enable for external buffers

Question asked by ChristianH on Oct 12, 2016
Latest reply on Oct 21, 2016 by Jithul_Janardhanan

Hi,

 

I'm using the ADSP-21469.

I've tried to use the pin buffer enable signal from the SPI to control an external buffer.

 

Normally you enable the MISO output (DSP is slave on the SPI bus) like this

SRU(SPI_MISO_O, DPI_PB02_I);      //MISO to DPI pin 2
SRU(SPI_MISO_PBEN_O, DPI_PBEN02_I);      //pin buffer enable for DPI pin 2

 

I tried to

SRU(HIGH, DPI_PBEN05_I);      //set as output
SRU(SPI_MISO_PBEN_O, DPI_PB05_I);      //pin buffer enable to DPI pin 5

 

The output on DPI pin 5 is low when I try to read from SPI.

I was surprised as I thought that the SPI_MISO_PBEN_O signal will be HIGH to enable a pin as output.

 

Where is my mistake?

 

Regards

Christian

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