2019-04-05 12:59 AM
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 :
Thanks!
2019-04-05 01:24 AM
> I suppose my options are either :
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.
2019-04-05 01:26 AM
This might help - Extending the SPI bus for long-distance communication
2019-04-05 01:47 AM
Thanks! reading now
2019-04-05 01:49 AM
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?
2019-04-05 02:18 AM
Ethernet
One could likely fake a version without magnetics for point to point.
2019-04-05 02:27 AM
> 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.
2019-04-05 02:29 AM
Ethernet is good.
Backup would be monodir link
Check on DS90LV031A cmos to lvds to cmos
2019-04-05 02:48 AM
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.
2019-04-05 02:52 AM
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.