[RFC 00/24] OMAP serial driver flow control fixes, and preparation for DMA engine conversion

Jon Hunter jon-hunter at ti.com
Thu Oct 11 10:05:22 EDT 2012

Hi Sourav,

On 10/11/2012 05:21 AM, Sourav wrote:


> I already enable software flow control and did the testing on beagle,
> where things are working fine
> after off mode.
> But if I enable hardware flow control, the teraterm does not allow me to
> load my fs and uImage from mmc.
> If you have any pointers on how to test hardware flow control, I will
> like to do that on my beagle board.

For h/w flow control, you need to check if the CTS and RTS signals are
being brought out to the serial header on the beagle-board. Looking at
the schematics for the 3430 beagle board, it appears that only the UART
RX and TX signals are available on the serial header. Therefore, I don't
believe you can test h/w flow control using the console with that board.

I do see that you can access all the UART2 signals (RX/TX/CTS/RTS) via
the expansion connector on the beagle. However, to connect to a serial
port on a PC you need to have a voltage level-shifter in-between. There
are some companies out there that make them [1], but you need to make
sure you have one that can support a 1.8V input.


[1] http://elinux.org/RS232_Level_Shifter

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