In the meantime I had contact to TI customer support.
They confirm, that there is a "problem" that DTC is not resetted after PUC. So
they recommend resetting DTC manually after PUC in the way I proposed and also
implemented in my code:
That is sequence-of-channels (A6-A0), physically not using A2, A4.
DTC for automatically transferring the 7 conversion results in one-block mode
and IRQ after one-block transfer has finished.
After this init the DTC is in IDLE (User-Guide, State-Diagram 20-10)
and waiting for ADC10MEM to be written to.
After initialization, ADC measurement ist startet every 100ms and in the
corresponding ADC10-ISR I do again a write to ADC10SA:
to IDLE again the DTC according to User-Guide, State Diagram 20-10.
Everything works fine ;-)
BUT....
If I do a SW-reset (WDT access w/o password) or let the WDT expire, a PUC is
generated, leading to another initialization as described above.
But then the DTC is not working any more. ADC10 conversion works, as I can see
in a plausible conversion result in ADC10MEM,
but DTC is not initiated and therefore no IRQ is generated.
It seems, that DTC keeps in IDLE-State after PUC and writing to ADC10SA (in the
init) deactivates DTC instead of putting it in IDLE as intended.
My workaround is to first reset DTC by setting ADC10DTC1 = 0x00 at
initialization before activating:
I don't know if this is a bug or if it is intended...
... but I think it is not obviously clear from reading the user-guide...?!
Anyone else out there having similar problems... or solutions?