From the datasheet
.17.6 Configuring Analog Port Pins
The ADCON1, TRISA and TRISB registers all configure
the A/D port pins. The port pins needed as analog inputs
must have their corresponding TRIS bits set (input). If
the TRIS bit is cleared (output), the digital output level
(VOH or VOL) will be converted
Which I read as saying tris has to be set along with adcon1 to make it analogue?
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