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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

OP said 20Mb/s (megabits), not 20MB/s

Dvorak.Peter
Senior II

My 2 questions are:

Is power and ground common to both devices.

Is this link ever unplugged

Exactly. I read it as 20 Mb and the OP hasn't edited the post.

USB might also be worth a look, supposedly 480 Mb/s there, although I think that is overly optimistic for the ST implementation.

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

It could be a fun idea to have QSPI as slave mode on STM32. Then we would have many scalable options to exchange data between 2 MCUs with direct memory mapping (read and write eventually).... to add to the STM32 Wish list?

Yes, the ground is common.

They work only with each other, connected via a connector that I'll add, depending on the chosen protocol.

I would use :

SPI

Ethernet 1m CAT5 patch cable

RJ45 connectors

RS422 tx rx chips or RS485 transceivers

100 ohm termination on each pair

Make sure that on the receiving side you sample in the middle of the data cycle.

TI SN65HVD7x 3.3-V Supply RS-485 With IEC ESD protection is rated up to 50Mb/s

http://www.ti.com/lit/an/slla173a/slla173a.pdf

S.Ma
Principal

Both the transeiver which diff the signal and the peripheral in the MCU must sustain the speed.

Otherwise, multiply the peripherals on each side to widen the bus...