0

I am currently working on a Raspberry pi (Jessie Stretch), the issue is that I want to connect two FTDI FT2232H serially at 12 Mbps, but because 12Mbps is not a standard speed Raspbian does not allow me to add that baud rate. I would like to know if someone has transmitted at that speed or if someone knows how to achieve the Bit rate of 12 Mbps with the maximum baud rate in Raspbian (4,000,000) .

PS: I changed the UART clock to 64,000,000, modified the "termbits.h" library and created termios structures, but nothing worked.

Thanks.

GerardoHdez
  • 1
  • 1
  • 3

1 Answers1

0

The data sheet for the FT2232H does advertise it supports 12 Mbaud (not 12Mbps). But it looks like it comes in different modules with support for RS232, RS422, and RS485. The most typical being RS232.

I've never heard of anyone operating a RS232 connection at 120000000 baud. The typical maximum that almost everything supports is 115200. The highest I've seen is 921600. Typical RS232 cables started running into interference issues at the higher baud rates.

I suspect the 12Mbaud spec is for RS422/RS485 operation which requires different cabling and is designed for higher speeds.

If you're using an FT2232H with RS232, the speeds you're looking for are likely unrealistic. If you're using it with RS422/RS485 you can probably get there, but it will be a much more specialized endeavor. It does look like Linux does support RS485. But there's not nearly as much documentation out there as for RS232.

Can you provide any more information about the USB adapters you're using?

Michael Powers
  • 1,970
  • 1
  • 7
  • 12
  • 1
    I'm doing a PPP connection, actually I have baud rate on 4,000,000, I know that Baud Rate <= Bps that's why I think that is possible to do that. – GerardoHdez Oct 10 '18 at 14:35
  • What specific adapters are you using? The FT2232H is just a UART chip, there's more to the adapters than just that component. How did you cable between the adapters? Which standard are you using (e.g. RS232, RS422, RS485)? – Michael Powers Oct 10 '18 at 14:47
  • Micro USB-USB attached to the UART with RS232. – GerardoHdez Oct 10 '18 at 17:02