ZHCSJK5B January 2018 – November 2019 TCAN4550-Q1
There are internal pull ups and pull downs on critical terminals to place the device into known states if the terminal floats. See Table 5 for details on terminal bias conditions.
|TERMINAL||PULL UP or PULL DOWN||COMMENT|
|SCLK||Pull up||Weakly biases input|
|SDI||Pull up||Weakly biases input|
|nCS||Pull up||Weakly biases input so the device is not selected|
|nWKRQ||Pull up||Weakly biases output when using internal voltage rail. When using open drain configuration an external pull up is be needed.|
|RST||Pull down||Weakly biases RST terminal towards normal operation mode|
The internal bias should not be relied upon as only termination, especially in noisy environments but should be considered a failsafe protection. Special care needs to be taken when the device is used with MCUs utilizing open drain outputs.