S12ZVH128 has issue when opearte at 3 V.

[rajnirajpoot]

When supply volatge is in between 6 to 7 V , i am getting 2.9 to 3.2 V at Vcc. At this time by default i am getting high voltage at s port , PS2, PS4, and PS5 MCU Pin 91,93,94. and my Tell-Tales .

what the reason for that?

How can i solve it ? Please help.

[danielmartynek]

Hi,

These pins have pull-ups to VDDX enabled by default. So you measure there 2.9 … 3.2V, right?

Do you use EVB or your own board? With the external or internal power transistor? How do you configure CPMUVREGCTL register?

Regards,

Daniel

[rajnirajpoot]

Hi Daneil,

Thanks for your reply,

we are using our own board with external power transistor . CPMUREGCTL is set to 0x05.

Regards,

Rajni

[danielmartynek]

Hi Rajni,

It should be set to 0x06 if you use external transistor.

Regards,

Daniel

[rajnirajpoot]

Hi Daniel,

After setting to it 0x06 , the status of pins are same.

Regards,

Rajni

[danielmartynek]

Hi Rajni,

Where exactly do you measure 2.9 - 3.2V? VDDX? And 6-7V is on VSUP pin?

Because 2.9V is below typical threshold value of Low Voltage Reset.  

There could be a problem in your hardware design.

Did you follow AN4721 S12ZVH Hardware Design Guidelines?

Regards,

Daniel