How to use serial with custom baud rate

Hello everyone;
I have a apalis imx6 SoM installed on ixora carrier board.
Apalis is running yocto bitbaked bsp 6.2 reference minimal image.

I want to make apalis serial communicate with some other device.
The other device is using 8.250.000 Bit/second(Baud rate) configuration.
So, I want to communicate at 8.250.000 Bit/second speed.

I will use ttl level units(Uart 3,Uart 4) on x27 extension connector.
I wont use rs232 level units(Uart 1,Uart 2).

How can I reach such configuration?

From userspace, one can use the command line utility stty to configure the serial speed. Then the port can be treated as as a regular file:

# stty -F /dev/apalis-uart1 115200
# echo Test > /dev/verdin-uart1

I couldn’t make stty to work at 8250000 bit/s baud rate.(It says invalid argument)(Max possible was 4 Mbit/s)
Same goes for minicom;
From settings menu,i was able to select max speed of 4 Mbit/s.

As shown in the link,
I tried diving the baud base to achieve custom baud rate.

But for UART 1,2,3,4:
It said, my baud base was 5 000 000

If thats a barrier,I can use USB0 also.
It says USB0 has 60 000 000 baud base

Can I USB0 with a fast ftdi converter to reach 8.250.000 baud rate?

Or ftdi converters are designed to work at specified baud rates?

It’s HW limitation of iMX6 System on Chip -

5.9 UART
The Apalis iMX6 provides up to five serial UART interfaces. Four of them are available on dedicated UART pins as defined in the Apalis standard. The fifth UART is only available as an alternate function. This fifth UART is not compatible with other Apalis modules.

UART Features - High-speed TIA/EIA-232F compatible (up to 5 Mbit/s)

(Apalis iMX6 datasheet)

The Apalis iMX6 has four USB2.0 (480 Mbit) interfaces, so theoretically, it is possible to reach a baud rate of 8,250,000 with a fast USB-to-serial adapter if the latter is supplied with Linux drivers capable of properly handling such a speed.

Dear @UfkuAcik,

Do you have any updates on this topic?