Chip: Freescale MK10DN512ZVLL10-4N30D (Kinetis K10)
Issue: ADC module/Peripheral conversions slowing down after 30-90 days and subsequently stalling/damaged permanently.
No of chips affected/damaged: 20 Nos.
Core Clock: 100Mhz
Bus Clock: 50MHz
ADC Operating Frequency: 50/8=6.25MHz
Hardware Average: No/Disabled
Long Sample: Yes
Long Sample clocks: Extra cycles
Total ADCs connected: 11
No. of Differential channels connected: 4
ADC Resolution :16-bit
No. of Single-ended channels connected: 7
ADC Resolution :16-bit
In-depth Problem:
- The chip ADC module works as designed/engineered/coded in our production line & factory testing.
- Once the chip is working in real-world application(industrial data aquisition), its works fine for atleast 30 days.
- The trouble starts anywhere between 30-90 days where the ADC conversions really slows down & ultimately freezes.
- Henceforth the aforementioned Chip-ADC module absolutely doesnt work on any valid ADC input signal.
- Once the ADC clock is lowered or increased in code & reflashed, the ADC module reworks but just for a day or two.
- Basically dead for future ADC conversions.
- The code also uses FTM that is derived from Bus clock.It works absolutely perfect.
- Rest all of the chip modules work as expected.
- No heating or physical damage observed or loose solder contacts.
- The VREF & VVA are shorted=3.3V same as the supply of the chip.
- The VREFH & VREFL voltages are steady & corresponding pins in place.
- No. of chips failed in this fashion ~20 Nos at different geolocations.
Attached is the Code* for Core clock, ADC clock & ADC reading.
Also attached is the schematic* for reference.
*Only ADC section.other details/specifics taken out
Please acknowledge, analyze, diagnose & suggest what is going wrong/what is causing ADC to damage/any corrections in code or schematic.Any suggestions will be appreciated.
Brij
