SLLSF28C December 2018 – June 2022 TLIN2441-Q1
PRODUCTION DATA
This pin determines if the TLIN2441-Q1 watchdog is programmed by pin strapping or by SPI. At power up, the device monitors this pin and determine which method is to be used. When tied to GND, the device is pin programmable, and when connected to a high-Z processor I/O pin, the device is set up to support SPI. In SPI mode if the LDO is being used to power up other circuitry than the processor a mismatch can take place if using the 5 V version of the device and the processor supports 3.3 V. All I/O in the device are set up to work with a 3.3 V processor but if the 5 V LDO is being used for the processor requiring the I/O to be 5 V then an external resistor pulled up to VCC. This makes the I/O 5 V.
The behavior of the microprocessor used must be understood if connecting to this pin to control whether the device is to be pin controlled or SPI controlled. There is an internal pull-up that sets the device in SPI control mode. If the processor pin drives low during power up, the device is in pin control mode. To specify pin control mode place and external pull-down resister to ground.