• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 396 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TCA6416A: Several questions of INT pin

Hirotaka Matsumoto
Guru 27525 points
Part Number: TCA6416A

Hi all

Would you mind if we ask TCA6416A?

<Question1>
On the datasheet Figure32, what does it mean tir?
Does this situation mean Data into port=Data From portm, so finish of read?

<Question2>
On the datasheet Figure32, what is the condtion which INT returns to high?
Is it to read the data which an input ports change state?
Could you let us know the condtion which INT returns to high?

<Question3>
If there is no changes of input ports, does INT port remain high despite of Read/Write?

<Question4>
When the device is reset operation, what does INT operate?
-Power Up Default : input setting
-If there is the difference between Q output of Input Port Resister and actual port inputs, does INT operate?
-Input low during Power on / Reset, does INT operate?
-Until the device are read input setting ports, does INT remain Low? Or, by writting configuration resister, does INT pint returns to High?  

Kind regards,

Hirotaka Matsumoto

  • 0
    TI__Genius 17555 points

    Hello Hirotaka-san,

    I will go through your questions one at a time.  

    1)   tIR is the interrupt reset delay time. This is the time it takes to either have the INT pin reset or the INT pin assert after the device has acknowledged.

    2)  The nINT goes high once the input port register has been read. It will not go low until another state change occurs at the input pins.

    3)  The nINT pin will remain high assuming not state changes at the input pins. Reading the reading the input port register will not make it go low and writing to an input port will not change the nINT signal because writing to the input port register isn’t possible because it is read only.

    4a.) When the part is in RESET the INT pin is open so the voltage on the pin depends on what the pull up resistor is tied to and the voltage level of that supply.

    4b.)  It is possible that the interrupt pin status could change while VCCP ramps up or down.  It depends on the pull up or down resistance and the capacitance on the pins.  If the bus has low capacitance and their are pull-up or pull-down resistors on the pins it should not trigger an interrupt change, but I recommend you read all the input registers to assure you start you system in a known state. 

    4c.) nINT will remain low until the input register is read.  Writing to configuration register does not clear nINT.

    I think I answered all your questions.  Let me know if you need more clarifications.

    -Francis Houde