AnsweredAssumed Answered

KEA8 internal temperature sensor

Question asked by Alessio De Marchi on Jan 13, 2017
Latest reply on Feb 15, 2017 by EARL GOODRICH

I try to use the internal temperature sensor, I'm using kea8 kinetis microcontroller.

When I sample an ordinary analog input, from external pin, it is all right, but when I try to sample an internal analog channel (Vbandgap or temperature sensor) the value that I have obtained is not consistent, very unstable and change if I start the conversion mode. For example, starting the bandgap sampling by:

ADC_SC1 &= ~0x0000001f;

ADC_SC1 |= 23;   // sampling bandgap channel

obtain the result from about 0x300 to 0xaff

 

elsewhere by setting

ACD_SC1 = 23 | INTERRUPT_ENABLE_MASK;

the result is from 0x100 to 0x12f;

 

The ADC is configured for long sample time and with different clock frequency (busclock = 5 to 20 MHz, ADCLK = busclock /4 to 16).

 

Any suggestion to solve my problem?

Outcomes