DRV8860: DOUT on 3.3V Input

Christoph,

DOUT is connected to MSP430's P3.2 pin which can set an internal pull-up for DOUT.

Since MSP430 can support this function, I don't have any concern.

Thank you, Wang Li for the quick Reply.

The internal Pullups of the MSP430 are typical 35k, the Pullup in the DRV8860 is 1.4k, so the Voltage on the Pin goes over VDD and will be truncated by the internal Clamping of the MSP430.

That's what makes me wonder why they dont use a divider or some Kind of voltage Translation.

I know from the C2000 that you have issues if you let current flow through the clamping, f.i. false measurements on other anlog Inputs.

Thats why i'm sceptical in this case. 

Christoph,

You are right. For a final application circuit, a 2.2kohm pull-down resistor on DOUT should be added to bring the voltage level to a normal range. Also, to make sure no back drive current, you can put a diode between MSP430 and DRV8860 DOUT.
On the EVM, MSP430 internal has a diode between P3.2 pin and DVCC which can handle 2mA. So, it doesn't get a trouble.