TIC12400-Q1: TIC12400-Q1 some question

Hi Lawrence,

Lawrence He said:

Q1: in polling mode, only IN PIN status to change to wake up MSDI? Could possible SPI pull High or Low to wake up?

The TIC12400-Q1 doesn't go to sleep itself and it instead is typically placed in a low power "Polling Mode" that will allow it to still monitor for events that can be used to wake up the MCU that has been put in sleep mode.  The TIC12400-Q1 uses the Interrupt (/INT) pin for this purpose, so any of the device's interrupt bits can be used cause a state change on the /INT pin and wake up the MCU. 

Typically IN Pin status changes are used for this, but the other events such as an over or under supply voltage, high temperature warning or shutdown, or ADC and Wetting Current diagnostic error, etc. could be used.  However, simply pulling a SPI pin high or Low would not likely cause a wake up.  If this did create a SPI error, then it may be used, but the device would likely need to see at least one clock cycle while the CS pin is low.

Lawrence He said:

Q2: in polling mode, INT pull Low need period is?

I'm not sure I understand the question.  The INT pin is the interrupt pin and if the Switch State Change (SSC) interrupt is enabled for a particular INx pin, the INT pin will transition low when the device detects a state change on that particular pin.  The INT pin will remain low until the interrupt is cleared by the MCU if the INT_CONFIG bit in the CONFIG register is set to 0h (default) for Static mode. If the INT_CONFIG bit is set to 1h for Dynamic mode, the INT pin will repeatedly pull low for a period tINT_INACTIVE (1.5ms to 2.5ms) and then high for a period tINT_ACTIVE (3ms to 5ms) until the MCU clears the interrupt.

Lawrence He said:

Q3: about ADC is read IN PIN input current? or Wetting current?

The ADC does not read current, it reads voltage.  The wetting current flowing across the switch resistance connected to the INx pin creates a voltage drop according to Ohm's law (V = I * R) which is read by the ADC. 

The ADC self-diagnostic and Wetting Current Diagnostic uses this same principle by monitoring the voltage drop across internal resistances to verify the device is operating properly and is capable of detecting a state change on an INx pin. 

Lawrence He said:

Q4: what`s different TIC10024-Q1 and TIC12400-Q1? only ADC function?

The main difference is the TIC12400-Q1 has both an ADC and Comparator that can be used for switch state detection and the TIC10024-Q1 only has the comparator.  However, the TIC12400-Q1 also has a Matrix Mode that allows up to 36 inputs to be monitored in a row/column configuration using only 12 INx pins (4 to 6 pins to source current, and 4 to 6 pins to sink current).  But the primary functional difference is the ADC.

Regards,

Jonathan