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TLC5949: How to drive TLC5949

Jesse Liang
Prodigy 10 points
Part Number: TLC5949

Hi Professors,Our company is using TLC5949 in a project, but when I debug software driver for TLC5949, I have some question as below:

1.The TLC5949 shift register is 193 bits,dose it mean I can't use standard SPI bus to driver is? because 193 bits is  24 bytes + 1 bit

2.How to control the inner signal BLANK Bit?

3.which registers I need to config if I want to driver TLC5949,can you offer a initialization demo code ?

Thanks!

  • 0
    TI__Genius 12915 points

    Hi Jesse,

    1. Yes it cannot be supported by a standard SPI. You could send first 24 bytes and set it as GPIO for additional bit. 

    2. the BLANK bit is in the first control data latch, which could be referred to datasheet table 7.

    3. There is no default for almost all first and second control data latch. They need to be written firstly. Here is a sample code for TLC5948, which have similar protocol. You could take it as reference,

    2465.TLC5948A_MSP_EXP432P401R_nortos_ccs.zip

  • 0 in reply to Hardy Wu
    Prodigy 10 points

    Hi Hardy,

    Thanks for your reply! I can write control data and GS data to TLC5949 now. But there is another problem. We design 5 TLC5949s multiple Daisy-chained as datasheet in page 1.what my question is:

    1.When I write GS data to TLC5949 continuously, it's 16 channel output is Ok, but when I stop writing, it's output stop.So dose it has to write GS data to TLC5949 continuously to hold it's channel output?

    2.As our  5 TLC5949s multiple Daisy-chained design,How can I just control any output channel in any device? It seem that they are share the same GS data if I Write GS data continuously, because when LAT is rising, the data in common shift register is copy to TLC5949. It can't set one channel output individually when design as multiple Daisy-chained?

    Thanks!

  • 0 in reply to Jesse Liang
    TI__Genius 12915 points

    Hi Jesse,

    1. How you set the DSPRPT bit? if it is disabled, the output only turn on one display period.

    2.Yes you can control any output in the chain. You could send all 5 data packages, first data package is for the device at end of chain. Then a latch signal would update the data to the device respectively.