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TMDX570LC43HDK: TMDX570LC43HDK how to connect 2 RS422 device (consider 2 SCI devices)

Etantonio
Intellectual 920 points
Part Number: TMDX570LC43HDK

Hy,

in our project we need to connect the TMDX570LC43HDK board to 2 sensors having each one an RS422 interface,

How it is possible to connect such devices to this board?

Considering just one sensor it is possible to use the USB/serial/JTAG connector J7,

but how to connect two different sensors?

Could be useful the second JTAG Connector J4?

This is just a connector for an external JTAG debugger by my point of view,

it could be used to debug a board that already use the USB connector for a SCI,

is this right?

Please excuse me but I've a little bit of confusion about these points.

Thanks

Antonio

  • 0
    TI__Guru 59540 points
    Hello Antonio,

    I apologize for the delay in getting to this question but I am reviewing the HW and will be back to you soon. Also, since RS422 is a differential protocol, you will need some sort of transceiver or device to translate the differential signals to Digital signals the MCU can utilize. Since you are discussing connecting to SCI ports, I assume the protocol carried over the RS422 line is a standard serial protocol? Or, do the sensors require a different type of protocol other than SCI?
  • 0 in reply to Chuck Davenport
    Intellectual 920 points
    Hy Chuck,
    the protocol is serial, I can rearrange my question in this way:
    we need to connect 2 different serial ports to the board TMDX570LC43HDK,
    one serial port can be connected to J7 JTAG connector,
    but how can I connect the second serial port?
    I think it is not possible to use the 20 pin JTAG port for this purpose.
    Antonio
  • 0 in reply to Etantonio
    TI__Guru 59540 points

    Hello Antonio,

    The default SCI that you are referring to is SCI1 and is part of the LIN1 module (pins A7 and B7 on the PBGA). These are hooked up to the XDS100v2 as a virtual comm port. They are also accessible on the expansion header P3 (J11, bootom).

    For the other SCI ports, LIN2 is not available as it is muxed behing some N2HET2 pins. However, SCI3 an SCI4 which are muxed with some NHET1 pins are available on the P3 expansion header as well (J11 from bottom view in HDK userguide).

    From datasheet terminal functions table:

    From a quick look at the schematic, it seems the NHET1[17] is used for another function so it is, perhaps, not the best choice to select for another SCI. From what I have seen on a quick review, I believe SCI3 muxed behind the functions NHET1[06] and NHET1[13] could be used for a second SCI on the HDK. You can check these as well in the HDK schematic and user guide available on the product page located here: .

  • 0 in reply to Chuck Davenport
    Intellectual 920 points
    Thanks for this answer,
    I could use an usb to serial adapter and use sci3 as you suggested.
    Thanks again,
    Antonio