Problem in Hardware flow control - i.MX28

[prateekraghuvan]

Hi,

     I am using i.MX28 AUART1 for communication with XBEE module, in which i need hardware flow control.

When i open minicom with H/W flow control enabled. RTS line of Processor never goes low. because of which

there is no communication happening at all. But when i Connect RTS of Processor to CTS of XBEE and then

CTS of Processor to RTS of XBEE (Note that i do it in sequence that is manually with wires with some delay) It starts working.

if any one have any Idea why is it behaving like this, Please help. 

[PeterChan]

Hello Prateek,

I saw similar issue before and eventually found that the problem came from the serial cable itself. For the cable, the RTS & CTS signals at one end is connecting to same signals at the other end! After rewiring the RTS to CTS, the serial hardware flow control works.

In community, there is another i.MX28 AUART hardware flow control issue under discussion. Please also take a look to the thread https://community.freescale.com/message/311942#311942.

Regards,

Peter

[prateekraghuvan]

Hello PeterChan,

                         I have solved the problem as well in my case i was using AUART1 which has CTS and RTS pins configured as some other functionality in the kernel for EVK. I changed it to CTS and RTS and it works fine for me. Thanks for the link.