DLP4500: i2c read/write error

Diogo dos Santos

Prodigy 65 points

Part Number: DLP4500

Hello,

I'm trying to run a few tests with the dlp4500 i2c, using i2cset and i2cget.

But every register that I read it gets 0x00, even when I write something different, it still read as 0x00.

I uploaded this screenshot to show.

Is there a sequence to write the registers or is it other kind error?

Thanks

over 5 years ago

0 Diogo dos Santos over 5 years ago

Prodigy 65 points

The device recognize the dlp i2c at the address 0x1a, as the image below.

0 Philippe Dollo over 5 years ago in reply to Diogo dos Santos

TI__Mastermind 28005 points

Diogo,

Welcome to the E2E forums, and thanks for your interest in our DLP technology.

Do you have any I2C software besides the i2ctools built-into linux? I've had issues in the past with i2cget reading the wrong number of bytes (and therefore only reading 0x00 in bytes with offset 3 instead of offset 0/1.

Best Regards,
Philippe Dollo

0 Diogo dos Santos over 5 years ago in reply to Philippe Dollo

Prodigy 65 points

Thanks for the reply Phillippe,

I don't have any other software. Which one do you recommend? One that you know it works.

Diogo.

0 Hirak Biswas over 5 years ago in reply to Diogo dos Santos

TI__Genius 10925 points

Hi Diogo,

To properly write a value to the register you have to set the MSB of the register address as 1. For example, you are trying to write to the register having address 0x66, so you should call the function as i2cset -y 0 0x1a 0xe6 0x10 instead of i2cset -y 0 0x1a 0x66 0x10.

But while reading from the registers, you should put the register address as it is. i.e., i2cget -y 0 0x1a 0x66 for reading the value of register 0x66.

Hope this resolves your issue.

Regards,

Hirak.

0 Diogo dos Santos over 5 years ago in reply to Hirak Biswas

Prodigy 65 points

Thanks a lot Hirak, That actually resolved my problem!!

However, now I have a different issue,
Running a few tests, the i2c get/set often answer with an reading/writing error. After using the oscilloscope we saw that the clock signal drops to 1V instead of 0V when in low part of the cycle.

We are not sure if it's a problem with DLP4500 or the I2C master we are using (Nvidia Jetson TX1).
Someone had the same problem??

0 Hirak Biswas over 5 years ago in reply to Diogo dos Santos

TI__Genius 10925 points

Hi Diogo,

Here we are using the DeVaSys USB-i2C module and we are not able to reproduce problems! Could you kindly try another I2C master if possible?

Thanks and regards,
Hirak.

0 Hirak Biswas over 5 years ago in reply to Hirak Biswas

TI__Genius 10925 points

Hi Diogo,

Do you still need the answer to your question? If not we'll be tentatively closing this thread.

Regards,
Hirak.

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DLP4500: i2c read/write error