Kinetis K60 and K70 PDB-DAC misbehaviour

[masettic]

Hello,

I am writing to point out an apparent mismatch between K60 (and K70) actual PDB DAC interval trigger outputs behaviour and what I have found in the reference manual (page 933 of K60 Sub-Family Reference Manual, Rev. 2 Jun 2012 K60P121M100SF2V2RM).

In the manual it is clearly stated that "DAC interval counters are also reset when the PDB counter reaches the MOD register value; therefore, when the PDB counter rolls over to zero, the DAC interval counters starts anew."

It seems that this is not what really happens: the DAC interval counter does not reset but it goes on counting regularly sending triggers to the DAC buffer.

What I would like to know is if this is a known behaviour and if the error is in the reference manual or in the MCU masks.

Best regards,

Cesare

[apanecatl]

The expected behavior of the PDB interval counters is to be reset whenever the PDB counter is reset, once this is done the PDB interval counters will start counting normally again and when they reach the DACINT value they will trigger a DAC update. The information depicted in document K60P121M100SF2V2RM, page 934: "DAC interval counters are also reset when the PDB counter reaches the MOD register value; therefore, when the PDB counter rolls over to zero, the DAC interval counters starts anew" is correct, there are no errata neither known issues on this regard.

[masettic]

Hello,

any news about this problem?

Best regards,

Cesare

[masettic]

Hello Pedro,

have you ever tested this behaviour? It does not seem to work this way.

If, for example, I set PDB0_MOD to a value lower than PDB0_DACINT0 I'd expect no interval trigger outputs to be received by the DAC but this actually happens since I see the DAC output change periodically, with a period that equals PDB0_DACINT0. The same if PDB0_MOD is higher than PDB0_DACINT0: the DAC output changes periodically, regardless of the value written in PDB0_MOD. I have PDB0 setup in continuous mode with software trigger.

Let me know if you have any news about this.

Best regards,

Cesare