i.MX53 (or i.MX6) UART and DTE vs DCE

[mmichaelis]

Can anyone explain what use or benefit there is from changing the UART on an i.MX53 from the normal DCE mode to DTE mode?   The documentation is confusing.  Section 76.1.3 says that CTS is an input in DTE mode, but an output in DCE mode.  However, section 76.2.1.2.1 for CTS  says the signal is an output in both DCE and DTE modes.

[igorpadykov]

Hi mmichaelis

there are no special benefits, just direction of some signals are changed

please look at Table 90 "UART I/O Configuration vs. Mode" IMX6DQCEC

Best regards

igor

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[mmichaelis]

Does that mean that in DTE mode, the internal CTS logic is connected to the external RTS pin?

[igorpadykov]

yes, internally CTS logic is connected to the external RTS pin

as shown on sect.64.2 External Signals IMX6DQRM p.5173

Best regards

igor

[mmichaelis]

That does not make sense to me.  The UART chapter explains the CTS only in the sense of an output control signal.    There is no explanation of what the CTS does if it is an input.  The same logic applies to the TX and RX lines.    Either something is not explained properly in the documentation, or the UART does not work at all if it is switched to DTE mode.

[igorpadykov · Accepted solution]

yes, you are right

sect.64.2 External Signals IMX6DQRM p.5173

shows that RTS becomes CTS and vice versa.

~igor