DS90UB925QSEVB: DS90UB925/DS90UB948 cannot transmit interrupt signal through INTB pin

Hi Amy,

Thank you for reaching out to us for your inquire. Did you follow the procedure in 925 and 948 section 7.3.14 Interrupt Pin and 7.3.8 Interrupt Pin respectively? You also need to read the interrupt status pin to clear and release the signal.

Hope this helps. Let me know if you have further questions.

Aaron

Hi Aaron,

Thanks for your response.

The register of 925 serializer has been set to 0xC6[5] = 1 and 0xC6[0] = 1, However, when there is an interrupt on the touch screen, the INTB_IN pin of 948 will become low, but the INTB pin of 925 is always high. TDA2x interrupt processing function is triggered at low level, and the interrupt cannot be detected when INTB is always high. What may be the reason for this？

The INTB connection of 925 is pulled up:

INTB_IN of 948 hardware connection :

Regards,

Amy

Hi Amy,

Yes it will stay HIGH until you read the status register.

Aaron

Is the HOST reading the 0x0C (general status) register of 925 through I2C?

Hi Amy,

Yes. This is correct.

Aaron

Customer feedback said

In this way, the host should always read the value of 0x0c register, then the INTB of 925 will be pulled down and the host will trigger interrupt. Isn't this the way of polling? The interruption of the touch screen is equivalent to meaningless. The required interrupt is to trigger the host interrupt to process the function when the signal on the touch screen changes.

If the host does not need to actively read the register, can't the INTB of 925 transmit the interrupt signal of the touch screen?

Hi Amy,

Can you please confirm if this is correct? According to the description, customer would like to use the touch screen enabling the INTB_IN from 948 to 925 INTB. If the INTB_IN is toggled, the 925 INTB will latch and stay HIGH until you read the status register in order to bring it LOW.

Aaron

Hi Aaron,

I'm sorry, I didn't express the customer's needs clearly.

The customer needs to know that there is a signal change on the touch screen through 925 INTB interruption. The host is not required to actively read the status register. If INTB_IN is toggled, 925 INTB will trigger the host to enter the interrupt function.

Regards,

Amy

Can this method described above be realized?

Hi Amy,

As I described on the previous posted, The INTB on 925 is required to read the status register in order to latch it LOW. If you want to use the INTB for remote event where it is mirroring the signal from the deserializer. I would suggest you to use GPIO where it is configured, and it will propagate the pair with deserializer.

Aaron

If implemented with GPIO, do the deserializer and serializer need any special configuration?

Hello Amy,

Due to US holiday we are currently out of office but will be back in tomorrow to assist further. Thank you for your patience.

Best Regards,

Casey