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S12G VDDF for ADC calibration

Question asked by jinjingyang Employee on Nov 14, 2016
Latest reply on Nov 15, 2016 by Radek Sestak

Dear Sir,

 

According to S12G datasheet "1.17 ADC Result Reference", we can read ADC channel internal_0 to get the VDDF voltage.

With the converted  VDDF value and the stored VDDF value, we can calculate the accurate VRH.

There are following questions:

1) The stored VDDF is at 0x4022/0x4023.

Does this mean  that this value is erased when we erase and program the S12G MCU in CodeWarrior?

We cannot  erase the 0x4000 flash sector if  we want to use this feature?

2) According to the note:

"This implies that code must be executed from RAM. The “ConvertedReference” value must be the average of eight consecutive conversions."

It's just internal ADC channel sampling and conversion, not flash  erase and programming.Why does it have to execute in RAM for ADC operation? 

3) According to datasheet "Table A-30. Voltage Regulator Characteristics":

VDDF = 2.6V ~ 2.82V ~ 2.9V. Is this the voltage range for -40~125degC? It's the voltage spread across all parts?

Since the error for VDDF within -40~125degC is +/-20mV, does it mean that VDDF can be 2.6V~2.9V and the stored VDDF value at 0x4022~0x4023 follows the +/-20mV error. It doesn't mean VDDF = 2.80V~2.84V.

 

Regards,

Jason Yang

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