Post by thread:PIC 14000 A/D problems

Hi I am stumped by a problem that involves the A/D channel AN1. I convert two voltages on the A/D that is in a range of 0 - 1v.I use channels AN0,AN1. When I convert on channel AN0 I get a nice conversion and can see the charging and discharging on the CDAC pin like the following /| /| /| <- 1.0v / |___/ |___/ |__ <-0.0v now when I switch to the AN1 channel I get a counter overflow int. and the cap charges up to 5v ,but both inputs are the same (max 1v). I can see it charges to 5v by the wave form on the CDAC pin. which looks like: ____ ____ <-5v / | / | / | / | _/ |_____/ |___ <-0v I have checked that the BAISOFF bit in the SLPCON reg is set ,to make it a normal A/D input. The direction of the pins on PORTA is inputs for AN0,AN1 and the ADCON1 has bits 1 and 0 set as 1,0 respectively to make the first two pins of PORTA analog inputs ,and the rest digital ones. Is there something I missed ?Why doesn't the A/D module get channel AN1 at its input to convert it? Any input will be appreciated Thanks Corne

Hi people I've sent a question on the list a few days ago and thanks for the people that have responded but unfortunately I've tried all the things before. As soon as I select the AN1 channel for a normal voltage measurement I've disabled the zeroing network via the pin4 in the SLPCON reg and no luck. I gives me the described waveform, have anybody physically done normal voltage level measurements by disabling the Zeroing network? Can you give me a copy of the code ,please ?? Thanks Corne (Previous letter) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Hi I am stumped by a problem that involves the A/D channel AN1. I convert two voltages on the A/D that is in a range of 0 - 1v.I use channels AN0,AN1. When I convert on channel AN0 I get a nice conversion and can see the charging and discharging on the CDAC pin like the following /| /| /| <- 1.0v / |___/ |___/ |__ <-0.0v now when I switch to the AN1 channel I get a counter overflow int. and the cap charges up to 5v ,but both inputs are the same (max 1v). I can see it charges to 5v by the wave form on the CDAC pin. which looks like: ____ ____ <-5v / | / | / | / | _/ |_____/ |___ <-0v I have checked that the BAISOFF bit in the SLPCON reg is set ,to make it a normal A/D input. The direction of the pins on PORTA is inputs for AN0,AN1 and the ADCON1 has bits 1 and 0 set as 1,0 respectively to make the first two pins of PORTA analog inputs ,and the rest digital ones. Is there something I missed ?Why doesn't the A/D module get channel AN1 at its input to convert it? ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^