1452 with several ADC and DAC

sabry Question

Mar 15, 2015 00:00

Hi,

I would like to connect several ADCs and DACs to the 1452, i will use all of them at the same clock frequency (48kHz) in I2S format.

I would like to use the 1452 as a master clock for ADC and DAC. The 1452 will generate the LRCLK, BCLK and the MCLK>

I was wondering if i can connect for example the LRCLK0 and BCLK0 to both ADC at the same, connect respectively the SDATAout of the first ADC to SDATAIN0 and SDATAout of the second one to SDATAIN1 of the 1452?

I would do it also for the DAC, so LRCLK0 and BCLK0 to both DAC and SDATAOUT0 to the first one and SDATA1 to the second one.

It could help to spare several pins to get more MP pins available.

Thanks in advance for any help,

Sabry

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JohnTo Reply

Mar 16, 2015 00:00

Hello Sabry,

What you are looking to do should be possible. If you are trying to save on BCLKx and LRCLKx pins and enable GPIO functionality, you can set up the additional I2S serial ports to be a slave to one of the other on-chip serial port masters. Of course, keep in mind when connecting LRCLK0 and BCLK0 to multiple ADCs or DACs, you would need to be careful with board layout issues, such as source termination to reduce reflections and perhaps increasing the drive strength on the clock signals through the on-chip registers.

-JT

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sabry Reply

Mar 19, 2015 00:00

Hello John,

Thanks for the answer

this is exactly what we need. Since we want to add four SPI ram memory to the 1452, we need to control the SS pin of each RAM with the MP pins, we would like to use two DACs to the same LRCLK and BCLK. We have of course add resitors for the termination. This the same for the ADCs, we would like to use two ADCs on the same LRCLK and BCLK.

Each one will be on the left and right side of the DSP. If it's a problem, we can of course put both ADCs as close as possible from each other.

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