2nd UART - Where is it on the board?

Kurt New Member Posts: 146 ✭✭
The specifications mention that there are two high speed uarts on the board, that have a range of 300 and 3686400.

I know that one uart is on the 40 pin expansion connector (pins 8 and 10).

Was wondering where the 2nd UART is on the board. I am guessing it is part of the 10 pin connector that includes the two other USB ports.

Is there a board layout that includes these, such that if I am making my own hat, I might include connector to use these?



  • Dan O'Donovan
    Dan O'Donovan Administrator, Moderator, Emutex Posts: 241 admin
    There is one high-speed UART at pins 8 and 10 on the 40-pin connector as you correctly mentioned above. In addition, the RTS/CTS hardware flow control signals for that UART will be available on pins 11/36. I've just updated the pin layout description now to reflect that:

    There is a UART on the 10-pin connector as well as you say. However, this is not one of the "high-speed" UARTs - it is a legacy UART designed mostly for providing a console interface. But it could be re-purposed for other uses as well, and should support speeds up to 115200 bps, but will most likely be enabled for console use by default by the BIOS and by ubilinux so this would need to be disabled first.
  • Kurt
    Kurt New Member Posts: 146 ✭✭
    Thanks Dan,
    You might want to also update the next section down in that wiki page that says:
    2 high-speed UARTs are provided on the I/O header.

    These can support baud rates between 300 and 3686400. Note that hardware flow-control pins for the UARTs are not currently exposed on the 40-pin header
  • Dan O'Donovan
    Dan O'Donovan Administrator, Moderator, Emutex Posts: 241 admin
    :oops: I missed that! Thanks very much for pointing it out.
  • [Deleted User]
    [Deleted User] Posts: 0 mod
    May I know if both UART (on the 40 pins and on CN7) can be used in windows 10?