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TLC5929: about communication interface

Hardy Xue
Expert 3600 points
Part Number: TLC5929

Hi Team,

My customer's application is AR glass and we have some questions for communication on TLC5929 as below.

1. The pin of SCLK/SIN/SOUT, do they same with SPI interface? Could you simply explain our serial interface?

2. Due to customer's platform is Qualcomm, there are 2 types SPI can support which are Non-SSC (SPI devices are connected to SoC directly) and SSC (SPI devices are connected to a DSP first). Could they use one of them to control our TLC5929?

3. If we cannot use SPI to control, why not?

4. For controller selection, do we have MCU solution can provide to customer(like competitor's STM32)? 

Best regards,

Hardy

  • 0
    TI__Genius 12915 points

    Hi Hardy,

    1. The data format and timing requirements are similar. I think basically there are 2 differences comparing the serial interface of TLC5929 with a standard SPI. 1) the whole data package for one TLC5929 is 17 bits while SPI support 16 or 8 bits. 2) The SOUT is a shift resister output of TLC5929, which can be used for data input of the next IC, if a daisy chain structure is used. The GS or control resister cannot be read inside, so read function of SPI cannot be used.

    2. I think a standard SPI can support, with continually sending 3 8-bit data and LSB 7 bits set at 0, which is wasted and causes some transmission delay. If customer want to use a SPI to control, I recommend TLC59291 which support 16 bit data input. The flat bit is removed. It would be easier to modified from a SPI.

    4. We do not have a recommended MCU solution.

  • 0 in reply to Hardy Wu
    TI__Expert 3600 points

    Hi Hardy Wu,

    Thanks for your comments.

    1. So, we need to suggest customer to change to TLC59291 for support SPI interface. Am I correct?

    2. How to connect pin LAT/SCLK/SIN/SOUT on schematic?

    3. Do we have guidance(hardware and firmware) to let customer clearly know how they use SPI interface to control TLC59291?

    4. I remember TI have MCU products. Is there no suitable solution?

    Best regards,

    Hardy

  • 0 in reply to Hardy Xue
    TI__Genius 12915 points

    Hi Hardy Xue,

    1. Yes it is recommended to use TLC59291.

    2. They can be connected to GPIO directly.

    3. No we do not have one.

    4. I think almost all MCU could be used to drive this device, since the timing requirement is not strict. You could consult MSP430 team for a suitable one.