TCAN1146-Q1: Disable local wake up input and identify first power on

Hi Dongbao,

Dongbao Zhou said:

1. Disable local wake up input through internal register, TJA1145 (0x4C=0x00, disable both rising edge and falling edge). Local wake up pin connect to other ECU, there are lots of uncertain signal during sleep mode, we don't expect it wake up device through wake up pin.

There is no register setting that can disable the WAKE pin. However, if the customer doesn't want to use the wake pin they can just connect it to ground.

Dongbao Zhou said:

2. How to identify power-on and CAN bus wakeup? TJA1145: 0x61[4] indicate power on;0x63[0] indicate CAN bus wake up; for TCAN1145, does 0x51[6] indicate CAN bus wake up? does 0x52[6] indicate power on?

You are correct, you would have to look at the interrupt registers. As you said 0x51[6] is for a CAN bus wake up, 0x52[6]  is for the power of the device. Keep in mind that for the PWRON interrupt it's default state is 1, so if there is a power cycle you will see that interrupt turn to a 0.

Let me know if you have any further questions.

Best,

Chris

Dongbao,

To add to what Chris said in the first question, the customer can also configure the WAKE pin to wake only on a specifically timed pulse signal. This would eliminate the risk of random noise causing a wake event for the most part.

Regards,

Eric Hackett