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@PaulStoffregen Thank you Paul, that is super helpful. I really appreciate it, I think you have saved me a lot of time. Fantastic.

Hi Gef Those expansion devices over I2C will not be much good at all for analog signals. They are really suitable for low speed digital IO. There are SPI versions of these devices available that can obviously increase the update bandwidth...

Hi bigdlin, For a data point, my board has no issue running the SPI clock at 50MHz for the ADC I'm using with a Teensy 4.1.

This seems very curious and not the norm: Typically the SPI bus is shared and additional CS lines are used to select the chip you want to talk to. Why are they doing it this way? bigDlin do you have them wired this way? Is it working? Also I...

That chip produces 16 bit results ie 16bit multiplexed ADC.

Is the data actually 32bits? or is it a 24bit converter sending a 4byte result? Depending on the converter, some will allow the result (eg ADC) to be sent as 3 bytes (24bits) instead of the 32 saying you 25% throughput.

I had been using PCBWay for everything up until recently when they dramatically increased their pricing on 4 layer boards. A 100mm x 100mm 4 layer board from PCB Way is about 4 to 5 times the price of the same design from JLCPCB which I found...

SdFat is blocking for both read and write. There is a fairly recent thread where someone modified SdFat to do non-blocking reads, but not writes. There is a way, though, to limit blocking times to 5-6 us and avoid the very long blocking times of...

Looking at your loop, it seems that you will keep opening and writing to your file indefinitely. Is that why you have append as an option/mode?

Hi DrM My ADC input full range is only +-1.2V hence the +-4V is plenty of room. I am using these as my front end buffer amplifiers. They are working very well in my current application...

yeah that would be nice as well. Honestly anything at this point would be a game changer. I'm currently developing a fairly large program for a teensy 4.1 with freeRTOS and the software debugger (https://github.com/ftrias/TeensyDebug) just...

Hi DrM Looking good. How much current and at what voltage ripple are you getting out of your design? I have now used a charge pump device to do something similar but with 5V input and +-4V outputs. I have a DAQ board which requires a bipolar...

The following is a github repository with KiCAD files for a dual +/-5V supply that can be driven from USB power. github repository for dual supply When designing for microcontroller boards, it is tempting to try to do as much as you can with...

One thing to think over is that the Teensy 4.1 is not 5V tolerant so if at some time you have accidentally pulled up to 5V maybe you have damaged the I2C bus IO on the Teensy? Do you have an DSO or logic analyser to look at the signals?