• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 82 subscribers
  • Views 289 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMS320F280049C: TMS320F280049: Using TDO pin as I2CA_SCL

Shaoxing Ke
Expert 3590 points
Part Number: TMS320F280049C


Hi champs,

I am asking for our customer.  And the customer needs extra pin for GPIO(64-pin PM version ), is it a way to use the TDO as I2CA_SCL ?

First, when load the code to flash by the JTAG emulator(TDO, TDI, TMS, and TCK), and then when in the standalone mode (without JTAG emulator), the TDO used as the I2CA_SCL, am I correct?

Only need to be re-configured in SW as below, and design for multiplexing on hardware:

Are there other considerations/Concern? BTW, customer need JTAG, Nor consider cJTAG. Thanks~

  • 0
    TI__Expert 4060 points

    Hi Shaoxing,

    You can use TDO as I2CA_SCL by confihure the GPyGMUXn and GPyMUXn in the code.

    But you need to be care that after that you may cannot connect JTAG , then you can let the device in wait boot mode.

    Or you can use CJTAG , so you will no need to consider this case.

  • 0 in reply to Huihuang Chen
    TI__Expert 3590 points

    Hi Johnson,

    Just double confirm that customer does not consider c-JATG,

    And within the JTAG design and I2CA multiplex design, their both require the 10K ohm pull-up, and when first JTAG connected and load the code to the chip,

    and S/W also re-configured this Pin, and then the I2CA can work normally. am I correct? 

    In wait boot mode for the chip to promote the connection about JTAG? 

  • +1 in reply to Shaoxing Ke
    TI__Expert 4060 points

    Hi Shaoxing,

    In the standalone mode, if the code download to device successful, the I2C can working normally. but you may failed programming the code to device due to the external I2C circuit affect the JATG communication .

    And in emulation mode , you may lost JTAG connection or the I2C will not working normally.

    So i will suggest customer use cJTAG or you need to check the 10Kohm pull up resistor is suitable or not by monitor the waveform quality of TDO?

  • 0 in reply to Huihuang Chen
    TI__Expert 3590 points

    Hi Johnson,

    Got it, thanks~