Content originally posted in LPCWare by Cusko on Mon Mar 11 04:31:32 MST 2013
I discovered some problems with an ADC on the LPC1837.
1. If I initialize an I2C1 with the ports (P2_3 and P2_4) then the ADC0_1 and the ADC0_3 show some values even if they are zero. And when the ADCs have some value they have also some offset. Only if I lower a processor frequency to 24Mhz the ADCs show correct value or if I turn the I2C initialization off.
2. If I don’t have a sensor connected on the ADC0_3 and the ADC0_1 has some value, then ADC0_3 shows some value too. If ADC0_1 doesn’t have any value then ADC0_3 is zero too. If a sensor is not connected the ADC0_3 value must be zero and must not be correlated to value on the ADC0_1. (In the case of the problem 2 the I2C was not initialized.)
Is this some kind of errata or what?