Best way to transmit a file over one-way serial line?

displace · 02-21-2022, 02:15 AM

Hi.

Suppose you have two embedded linux devices that are connected with a one-way serial line i.e. a USB-to-UART device like /dev/ttyUSB0 on each end with only one wire (besides the GND wire) going from a TX pin on device 1 to a RX pin on device 2. This means the traffic can travel only one way (this is often called a data diode).

What is the best way to transmit a file over this line? Preferably with some error checking to see whether the contents on the receiving end are intact.

Thanks in advance.

rtmistler · 02-21-2022, 03:00 AM

1-wire.

Error checking is up to you.

displace · 02-21-2022, 06:49 AM

No, I was wondering, if there are any existing linux tools available for this task (i.e. transmit a data size, hash and payload) or do I have to write my own python script?
Just asking because I was about to start writing the program, and I don't want to finish the program only to discover an existing tool for the job.

Regards!

michaelk · 02-21-2022, 07:17 AM

I don't know of anything existing but would probably use xmodem or ymodem as an example without the handshaking.

pan64 · 02-21-2022, 07:20 AM

you can use whatever you want but if there is no way to report back what is the goal?
You can transfer file[s], checksums ...., you can run some tools to validate, but what would be the result?

rtmistler · 02-21-2022, 08:18 AM

Quote:

Originally Posted by displace

No, I was wondering, if there are any existing linux tools available for this task (i.e. transmit a data size, hash and payload) or do I have to write my own python script?
Just asking because I was about to start writing the program, and I don't want to finish the program only to discover an existing tool for the job.

Regards!

Yes, there is something existing:https://www.kernel.org/doc/html/late...1-generic.html

michaelk · 02-21-2022, 08:33 AM

That looks like the Dallas semiconductor 1 wire bus which uses different hardware and is actually bidirectional. I don't think you can do the same thing over a serial port.

rtmistler · 02-21-2022, 10:08 AM

Quote:

Originally Posted by michaelk

That looks like the Dallas semiconductor 1 wire bus which uses different hardware and is actually bidirectional. I don't think you can do the same thing over a serial port.

Dallas 1-wire is precisely what the OP described. This seems to be custom hardware nonetheless.

Not saying it is any more palatable option than just writing their own driver, but I feel that nothing exactly matching exists and they'd be best to use existing references to attain their goal.