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Is there any UART chip able to provide a full 9-pin DCE serial port?

WENBO LI
Intellectual 440 points
Other Parts Discussed in Thread: TL16C2552, MAX232

 

Is there any UART chip that can provide a full 9-pin DCE serial port?

A full 9-pin DCE serial port requires 5 outputs (DCD, CTS, DSR, RI, TXD) and 3 inputs (RTS, DTR and RXD) and a GND.

The UART chip like TL16C2552 could interface a processor through the data/address/control lines and provide the serial ports. However, the UART chip TL16C2552 can only provide a full 9-pin DTE serial port. A DTE serial port requires 3 outputs (RTS, DTR and RXD), 5 inputs (DCD, CTS, DSR, RI, TXD), and a GND; this is exactly what the TL16C2552 can provide from its serial port.

I am wondering:  is there any similar UART chip that can interface the processor and meanwhile can provide a full 9-pin DCE serial port?

What's the best solution to providing a full DCE serial port ?

  • 0
    Guru 227245 points

    I don't know whether there is a single-chip solution.

    But since all pins except Rxd and TxD are plain I/O signals, the MSP can simulate both versions without problems by its GPIO pins. And for the TTL/RS232 conversion, there are many deriates of the MAX232 series with varying numbers of inputs and outputs.

    Since the MSP has no external address/data bus, interfacing an external chip to do this job would be a slow, clumsy and a waste of resource.

    If your question was not MSP430 related at all, then maybe you posted in the wrong forum :)

  • 0 in reply to Jens-Michael Gross
    Intellectual 440 points

    I'm sorry I posted in the wrong forum. I should have posted it in the Interface forum.

    Thanks for your reply though.

  • 0
    Guru 35565 points

    WENBO LI said:

    A full 9-pin DCE serial port requires 5 outputs (DCD, CTS, DSR, RI, TXD) and 3 inputs (RTS, DTR and RXD) and a GND.

    Actually, only 3 of those ouputs (CTS, DSR, TXD) are really UART functions:

    • DCD = Carrier Detect - which is not related to UART operation;
    • RI = Ring Indicator - again, not related to UART operation.

    These signals would come from other logic functions...

     

  • 0 in reply to Andy Neil
    Guru 227245 points

    Andy Neil said:
    Actually, only 3 of those ouputs (CTS, DSR, TXD) are really UART functions:

    And of those, CTS and DSR (as well as the interpretation of DTR and RTS) are not necessarily hardware-implemented.

    While some UARTs (especially those with hardware FIFO for input and output) implement RTS and CTS in hardware (if enabled), those without FIFO won't necessarily do so. And DSR/DTR are terminal handshake signals and not UART operation related. (extended by RI and DCD for MODEM operation).

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