Getting high speed DAQ data off a Teensy 4.1

[Dr_Nic]

Hi I'm new to the Teensy eco-system FTR

I have a Teensy 4.1 interfaced with an EVAL-AD7606SDZ DAQ board.
I'm using Joshua Austill's AD7606 library and will be targeting a sampling rate of 100KHz.

So 16 bits x 8 channels x 100,000 = 1,600,000

I need to run for a minimum of 12 seconds so obviously memory is now an issue.

What is the best way to get this data out, either as its coming in or buffered in someway?

 

[h4yn0nnym0u5e]

16 bytes x 8 channels x 100,000 = 1,600,000

Eh?
16 bytes x 8 channels x 100,000Hz = 12.8Mbytes/s. For 12s that’s 153.6Mbytes.

Your best bet is a fast SD card with a pre-allocated file - there are many threads here about this. SD on the built-in SDIO socket can reach about 20Mbytes/s; you may well be able to run for considerably longer than 12s.

 

[jmarsh]

OP likely meant 16 bits, not bytes... A 128 bit ADC would be pretty damn impressive.

 

[Dr_Nic]

Eh?
16 bytes x 8 channels x 100,000Hz = 12.8Mbytes/s. For 12s that’s 153.6Mbytes.

Your best bet is a fast SD card with a pre-allocated file - there are many threads here about this. SD on the built-in SDIO socket can reach about 20Mbytes/s; you may well be able to run for considerably longer than 12s.

Typo will fix meant to be 16 bits not bytes

 

[h4yn0nnym0u5e]

OP likely meant 16 bits, not bytes... A 128 bit ADC would be pretty damn impressive.

Indeed it would!

Typo will fix meant to be 16 bits not bytes

Ah, different question then. 1.6Mbytes/s or 25.6Mbits/s. 12s duration gives 19.2Mbytes.

So … SD storage is pretty much trivial, apart from the high memory prices at the moment … Streaming over USB is doable, as long as you use a robust protocol like COBS to preserve data integrity … Or installing two of the newish 16Mbyte PSRAM chips would give you space for 20s of data.

Which of those is your best choice rather depends on a bunch of stuff you haven’t disclosed, like whether a USB tether is possible, how robust the system needs to be (you probably wouldn’t use SD in a rocket…), how many runs you envisage doing, how many systems you plan to make, etc.