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MAX3221E in AutoShutdown

Jim Sung
Prodigy 50 points
Other Parts Discussed in Thread: TRS3238E, MAX3221E

This is similar to a post of mine on the TRS3238E: http://e2e.ti.com/support/interface/etc_interface/f/392/p/117720/421462.aspx#421462.  In that particular scenario, we couldn't find a way with the "auto-powerdown plus" feature enabled, and still meets our usage, so we basically disable the "auto-powerdown plus" feature, and have the software manually shut the TRS3238E down.

However, we have another serial port with the MAX3221E, and this port needs to be able to transmit and receive reliably at all time, and we cannot afford to disable the "AutoShutdown" feature of the MAX3221E, so we seem to be caught between a rock and a hard place.

Our link partner may tri-state its TXD to conserve power, and we want to shut off our transmitter to conserve power, and each of us can generate messages asynchronously, and we don't want to lose characters.

Any suggestion will be greatly appreciated.

 

  • 0
    TI__Guru**** 165236 points

    Hello Jim,

    This situation is similar but not exactly the same.

    You will still need to manually turn the driver on and off, but you have more control on this device.
    The enable pin should be low; this will keep the receivers active all the time so incoming data will not be lost.
    The ForceOn and ForceOff pins should be tied together (unlike the TRS3238E example) and set high 100uS before a serial transmission and set low after all data is sent.

    On this device setting ForceOFF low will not affect the receivers.

    Regards,
    Ron Michallick