TLC5958: How to light on the LED matrix buy using two TLC5958 LED driver ICs ?

Wesley Lai

Intellectual 290 points

Part Number: TLC5958
Other Parts Discussed in Thread: LP55281, LED171596A

Dear Sir,

I designed a 23*23 RGB LED matrix and used two TLC5958 LED dirve ICs for circuit design.

The following documents were referenced:
1. TLC5958 datasheet
2. tidr683.pdf-tidr688.pdf
3. slva645_5_.pdf

Circuit design drawings such as attachment files.

LED Board.pdf

My MCU is using Nordic nRF52832, but I have been unable to properly illuminate the LED.

I have rewritten it with reference to this article and still cannot be lit normally.

TLC5958: sample code

Have any partners can provide the code of the 64*64 RGB LED matrix that is lit in the file "slva645_5_.pdf" to me?

over 6 years ago

0 Kenneth Du over 6 years ago

TI__Genius 14295 points

Hi, Wesley,

How about just testing your code for only one line of LEDs?

Please check the signals and make sure they meet the timing requirements.

The 64*64 RGB LED matrix is driven by NovaLCT-Mars V4.2.6 CTM23.0.1 controller.

Thanks.
Regards,
Kenneth

0 Wesley Lai over 6 years ago in reply to Kenneth Du

Intellectual 290 points

Hi Kenneth,

Thank you for your reply.

When we double check the souce code, we find some questions.

The biggest question is we can not sure the frequency of SCLK meets the minimum specifications of the TLC5958.

Our MCU can generate 1MHz(max.) to SCLK or GCLK.

So...how to determine the frequency of SCLK is what we want to know in the first step.

Dear Kenneth, can you help us ?

0 Kenneth Du over 6 years ago in reply to Wesley Lai

TI__Genius 14295 points

Hi, Wesley,

The GCLK and SCLK frequency have no minimum requirements but related to the expected frame refresh rate.

SCLK is related to frame rate and if your frame rate requirement is 60Hz, and you're using 16bit PWM for 23 RGB LEDs, the minimum SCLK frequency is:
60Hz*69CH*16bit*23=1.524MHz

You can refer this to determine your SCLK frequency.

Thanks.
Regards,
Kenneth

0 Wesley Lai over 6 years ago in reply to Kenneth Du

Intellectual 290 points

Hi Kenneth,

Thank you....

So...we need change the LED driver IC to meet this LED matrix.

We have see the TI products, and we select the new LED IC is LP55281.

We will using SPI interface in this IC.

But we are worried about the scan rate.

Do you have any suggestions?

0 Kenneth Du over 6 years ago in reply to Wesley Lai

TI__Genius 14295 points

Hi, Wesley,

How do you want to use LP55281 in this 23*23 RGB LED matrix? Still multiplexing?

Thanks.
Regards,
Kenneth

0 Wesley Lai over 6 years ago in reply to Kenneth Du

Intellectual 290 points

Hi Kenneth,

We will use 6 pcs LP55281 to connect the 23 RGB LEDs (69 columns).

And the nRF52832 have SPI interface & the SPI clock frequency can up to 8MHz.

SO...we think it can meet our request.

Wesley

0 Kenneth Du over 6 years ago in reply to Wesley Lai

TI__Genius 14295 points

Hi, Wesley,

It's not recommanded to use LP55281 in multiplexing topology.

Can you count your GCLK number?

Thanks.
Regards,
Kenneth

0 Wesley Lai over 6 years ago in reply to Kenneth Du

Intellectual 290 points

Hi Kenneth,

No, we not count GCLK number, because the frequency of SCLK has exceeded the capabilities of the MCU.

Under the MCU cannot be replaced, we have to use other solutions to illuminate the LEDs.

Do you have any suggestion ?

0 Kenneth Du over 6 years ago in reply to Wesley Lai

TI__Genius 14295 points

Hi, Wesley,

Would you check LED171596A?

Thanks.
Regards,
Kenneth

0 Wesley Lai over 6 years ago in reply to Kenneth Du

Intellectual 290 points

Hi Kenneth,

Thank you for your suggestion.

I will discuss with my team member.

Thank you a lot.

Wesley

2018.07.24

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TLC5958: How to light on the LED matrix buy using two TLC5958 LED driver ICs ?

TLC5958: sample code