I am using the G120’s onboard ADC with .NetMF 4.3 2014 RTM QFE1 and NETMF and Gadgeteer Package 2014 R5.
I understand there is a push to move to the TinyCLR OS, however I cannot move to the new libraries\framework just yet.
On rare occasions, the ADC values read from the LPC1788 may read 0 (and remains until the G120 is power cycled), despite the component monitored measuring a non-zero voltage. When this occurs, not all channels read 0, most work and usually only one channel doesn’t.
If this was a hardware issue with the chip I would simply replace the Cobra board with another, however I am seeing this across multiple boards.
My next thought was the 3.3v reference voltage to the ADC chip may not stable but then I would most likely see an incorrect voltage rather than a 0 from the ADC.
I was reading through the LPC1788 user manual, page 820 and the ADC control register has a Burst mode which reads through all enabled ADC channels.
Some further reading on NXP’s errata, page 6 says when reading from the ADC in Burst Mode, the read value should be obtained from the individual ADC channel registers rather than the Global Data Register.
- Are the G120 ADC reads coming from the ADC Global Data Register (GDR), or the individual ADC Channel Registers?
Apologies if this topic already exits, I have not found it.