Using the PiSound with MCC DAQ HATS on the RPi 4B

#1

I have designed a machine to test track parameters which involves using a couple of MCC DAQ HATs on top of an RPi; they use I2C for comms - I propose to place a PiSound on top of the DAQ HATs - I am hoping that the relevant pins - e.g. SPI, pass through the HATS so that a PiSound can be used on top.
The DAQ HATs provide I/O interface to a sensor RPi and an Instrument Panel Pi, and allow control and sensor reading.
The PiSound is used to digitise audio output from cameras (line voltage so should work with the PiSound) and send it from one Pi to the other as Ethernet packets. The other PiSound will process the sound and send it to a Digital Video Recorder, as well as a small headphone mixer.
I am using a RPi 4B as the processing required could pose an issue. The MCC DAQ HATS and the PiSound do the processing, while the RPi’s and Ethernet do the comms.
Now the burning question is: will DAQ HATS and the PiSound work together.; other wise I will need to use a separate RPi for each aspect and use an Ethernet switch to ‘join’ the two RPi’s together at each end.

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#2

Hey, which model(s) MCC DAQ hat(s) do you intend to use in particular? I’ll take a look into whether they are completely compatible with Pisound.

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#3

G’day, mate,
Thanks for replying.

MCC 118 - 8 input analogue HAT and MCC152 2 x PWM, output and 8 DIO

They have a digital - read binary - method of setting the board address on each board. They use I2C in the GPIO; where as PiSound uses SPI; I presume the other pins are power and housekeeping and possibly may be shared??

I subscribe to DIYODE magazine here in Australia and they have done a review on the Model 4 'Pi and apparently it is power hungry - the recommended 'Pi PSU should be used. My impression is that a low impedance PSU needs to be used.

Now, if the Model 4 is a spread a bit thin on the ground, will the Model 3 B do the trick, bearing in mind that Ethernet is involved - I presume that the Ethernet chip does the data to packet processing, leaving the 'Pi to do everything else, so there should not be any overhead there.

Once again, thanks for replying.

Regards

Don Pollard

BAppSc - EnviroSc-GIS

DipElectEng - Microprocessors and PLCs

DipIT - Network Engineering (and Database)

Cert III Electronics Trade inc High Reliability Soldering

Various Welding, Hydraulics, etc

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#4

In this specification of MCC 118, I only see the SPI interface mentioned, and it is on Chip Select 0, Pisound is on the same line. However, Pisound’s SPI is only used for MIDI communication. With a custom kernel module, it could be disabled.

Also, both Pisound and MCC 118 have ‘I²C hat eeprom’ on them, I am not sure how well they would play together, but this bit can also be worked around to manually load the Device Tree overlays as necessary (in Pisound’s case, sudo dtoverlay pisound has to be executed)

However, GPIO12, GPIO13 and GPIO26 are used on Pisound for controlling its ADC and DAC, MCC 118 says ‘Board Address’ in its their description. Their purpose on MCC 118 is a bit unclear, as they have address jumpers, I can’t find any info on their the GPIOs meaning.

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#5

Hi Giedrius,
Thanks for that. I have downloaded the datasheets as prompted.
Regards

Don Pollard

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