DS90UB941AS-Q1: How to configure the register 18h 19h (SCL_HIGH/LOW_TIME)?

Ansel Song

Part Number: DS90UB941AS-Q1

Hi Team,

In an actual system, how to configure registers 18h and 19h ? In other words, what is the recommended rate of I2C?

The customer is using the default value to find that the screen touch will fail, so this should be related to the I2C rate, so is there a recommended value for the I2C rate? Thanks.

Best regards,

Ansel

over 5 years ago

0 Casey McCrea over 5 years ago

TI__Guru** 103215 points

Hello Ansel,

The default rate is ~100kHz based on the register settings here. What is the target I2C rate for the customer?

Thanks,

Casey

0 Michael.Walker over 5 years ago

TI__Mastermind 19720 points

Hi Ansel,

Did you resolve your issue or should I close this thread?

Regards,

Michael

0 Ansel Song over 5 years ago in reply to Casey McCrea

TI__Expert 3890 points

Hello Casey,

Thanks, the customers use the default settings and find that the touch function will fail, mainly at the edge of the screen, so they want to know what rate we generally recommend.

Best regards,

Ansel

0 Michael.Walker over 5 years ago in reply to Ansel Song

TI__Mastermind 19720 points

Hi Ansel,

The 941AS with default I2C register settings should use an I2C rate of 100KHz. The I2C pull up value can be calculated with this document: http://www.ti.com/lit/an/slva689/slva689.pdf. What is your pull up value? The issue that you are having does not sound to me like an I2C issue from what you have described so far. Can you try to probe the I2C signals on the display board and then the I2C signals on the main board?

Regards,

Michael

Interface

Interface forum

DS90UB941AS-Q1: How to configure the register 18h 19h (SCL_HIGH/LOW_TIME)?