Wrong input voltage levels Kinetis K10

[bostångberg]

Hi, all!

I am using the MK10DX128VLL7 kinetis processor. And have some problems with the GPIO input voltage levels.The supply voltage is 3,3V and if i look in K10P100M72SF1 document table 1 the levels are:

  Input high voltage Min 0.7*3.3V = 2.31V.

  Input low voltage Max 0.35*3.3V = 1.155V.

When i measure on my prototype board the levels spreads and are not as the datasheet says.

For example:

PTB0

      Input high voltage 1,78V.

      Input low voltage 1,7V.

PTD2

     Input high voltage 1,74V.

     Input low voltage 1,3V.

The input high voltage level seems to be around 1,7-1,8V for all pins but the low voltage level spreds all from 1.15V to 1.7V. There is no spikes and the supply voltage looks good.

Has anyone any idea why the levels are not as datasheet says?

Thanks!

[pavel_krenek · Accepted solution]

Hi,

as you mensioned the datasheet says about the input ranges that Input low voltage Max is 1.155V and Input high voltage Min is 2.31V.

These informations mean that in the range between 1.155 V to 2.31 V is not guaranteed the correct logical level of the input signal.

Guaranteed:

0 V -> 1.155 V  = logical 0

2.31 V -> 3.3 V = logical 1

Best regards,

Pavel

[bostångberg]

Hi!

Thanks for your reply! Now when you say it it sounds logical.

Best regards,

Bosse