HATs and other add-ons • Logic level shifter recommendations

I am attempting to interface an Echo mic board to a Pi and have an issue with the logic levels.

The board uses 4 x tlv320adc3101 for the microphones and they use the following voltages:

• AVDD (Analog Voltage) 2.6V - 3.6V
• DVDD (Digital core voltage) 1.65V - 1.95V
• IOVDD (I/O voltage supply) 1.1V - 3.6V

Unfortunately DVDD and IOVDD are hardwired together which makes IOVDD range the same as DVDD (1.65V - 1.95V). In addition to this the digital highs and lows are defined as follows:

• Input Low = 0.1 x IOVDD
• Input High = 0.7 x IOVDD
• Output Low = 0.1 x IOVDD
• Output High = 0.8 x IOVDD

This would make the output high voltage 1.95 x 0.8 = 1.56V which is unlikely to trigger the PI.

Therefore I need a logic level shifter, but...
The tlv320s support sample rates from 8 kHz to 96 kHz and word lengths from 8 to 32 bits. Since there are 8 channels this makes the bitclock range from 1.024 MHz to 24.576 MHz.

What I would like is a logic level shifter that can handle 25 MHz bidirectionally. What I would settle for is one that could handle 5 MHz so I could record at 32 bits @ 16 kHz minimum.

Any recommendations?

Statistics: Posted by SynAckFin — Sun Sep 15, 2024 8:48 am

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