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Best way to transfer fast data over 1 meter cable

ISeed
Senior

Hello, all!

A quick question: if I want to transfer data between 2 STM32 devices, which are located 1 meter apart, at a rate of at least 20Mb/s, in bursts of 300KB at a time. what is the best way to do so?

The communication is unidirectional.

I suppose my options are either :

  • SPI (which I'm not sure about, because I understand it's only good for up to ~30 cm)
  • 8 parallel data lines with a clock, which allow me to effectively cut the bit rate by 8, but I don't know if it will actually be reliable and if suitable cables with enough wires are available for purchase.
  • Some other possibility I'm not thinking about?

Thanks!

16 REPLIES 16
AvaTar
Lead

> I suppose my options are either :

  • SPI (which I'm not sure about, because I understand it's only good for up to ~30 cm)

With proper drivers (I mean hardware) and homogenous, impedance-matching cables, this works.

I had been on a project that successfully used SPI over ethernet patch cable as means of communications.

A higher level protocol to detect and correct transmission corruptions is advised, though.

Thanks! reading now

Thanks! These drivers, are they independent HW components I can look for, at, let's say, DigiKey? How are they called?

Do some STMs happen to have those on board?

Ethernet

One could likely fake a version without magnetics for point to point.​

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Up vote any posts that you find helpful, it shows what's working..

> These drivers, are they independent HW components I can look for, at, let's say, DigiKey?

Yes, so much I remember. But not a specific name, it was more then 6 years ago.

In general bus drivers with an output impedance matching that of your cable. Ethernet cable and RJ45 connectors are a relatively cheap solution.

Perhaps differential drivers for RS485, CAN, or similar. The transceiver chips are usual not specific for said protocols, only the bus levels. Bandwidth should be sufficient, I would say about 100MHz for a digital 20MHz signal.

Or asymmetric one's, like 74 series bus transceivers.

S.Ma
Principal

Ethernet is good.

Backup would be monodir link

Check on DS90LV031A cmos to lvds to cmos

Uwe Bonnes
Principal III

20MB/s and 100 Mb Ethernet does not fit together. 20 MB/s is > 160 Mb/s.

Does the llink need to be bi-directional? Does the link need to be flexible with a cable or can it be a backplane. Maybe some serdes chip connected to the FMC can do the job.

Otherwise STM32MP1 has Gigabit Ethernet.

I think this is an ambiguity in the OP.

SPI would not be able to manage 20MByte/s, neither would the receiver really be able to sustain this data rate for sensible package sizes.

I suppose he meant 20MBit/s.