[F767ZI] Sampling and storing Measurement Data

[Armin L.]

Posted on February 16, 2018 at 01:03

Hello!

I want to start a project with the NUCLEO-F767ZI soon. In this project I want to measure some quantities with up to 100 kSamples/s and store the data.

Would it be physically possible to have the data either stored to an SD memory card (via SDMMC interface) or sent via Ethernet with up to 10 MB/s in realtime and still having some computing power to execute additional calculations on the MCU? Or are there restrictions on the achievable data rates?And which memory device or data transfer protocol would you suggest for that purpose in general?

Thanks in advance!

#data-transfer #ethernet #sdmmc

[Tesla DeLorean]

Posted on February 16, 2018 at 10:06

Seems like that would be pretty close to the bandwidth limit of those two interfaces.

[Armin L.]

Posted on February 17, 2018 at 18:20

I thought that the datasheet states about 50 or 100 MB/s as data rate limit. Or are those theoretical limits that cannot be achieved in real operation?

[Tesla DeLorean]

Posted on February 17, 2018 at 19:56

Don't confuse bits (Mbps) and bytes (MBps)

Ethernet 10/100 would be a maximum of 100Mbps , which is going to be something less than 12.5 MBps for practical purposes.

SD cards are highly variable in their performance, clocking the bus at 50 MHz(SDIO 4-bit) might deliver 13 MBps writes on a quality SDXC card using large aligned blocks. Reads likely closer to 20 MBps.

[Bogdan Golab]

Posted on February 17, 2018 at 20:41

Assuming full-duplex. In half duplex the real performances drops as you have to take care of the csma/cd.

[Tesla DeLorean]

Posted on February 17, 2018 at 21:33

I'm figuring a pretty asymmetrical use case. Anyway the ceiling is pretty low and falling.

[Armin L.]

Posted on February 17, 2018 at 21:46

Is 'duplex' referred to Ethernet or SD?

[Armin L.]

Posted on February 17, 2018 at 21:46

And what about 3 MB/s? Or I have to decrease the sampling frequency...

[Bogdan Golab]

Posted on February 17, 2018 at 21:51

I was commenting the Ethernet

[John Craven]

Posted on February 17, 2018 at 23:51

sorry are we talking adc samples?

stored raw? no processing?