Datasheet

dsPIC30F5011/5013
DS70116J-page 134 © 2011 Microchip Technology Inc.
FIGURE 19-5: ADC OUTPUT DATA FORMATS
19.13 Configuring Analog Port Pins
The ADPCFG and TRIS registers are used to control
the operation of the ADC port pins. The port pins that
are desired as analog inputs must have their corre-
sponding TRIS bit set (input). If the TRIS bit is cleared
(output), the digital output level (V
OH or VOL) will be
converted.
The ADC operation is independent of the state of the
CH0SA<3:0>/CH0SB<3:0> bits and the TRIS bits.
When reading the Port register, all pins configured as
analog input channels will read as cleared.
Pins configured as digital inputs will not convert an ana-
log input. Analog levels on any pin that is defined as a
digital input (including the ANx pins) may cause the
input buffer to consume current that exceeds the
device specifications.
19.14 Connection Considerations
The analog inputs have diodes to VDD and VSS as ESD
protection. This requires that the analog input be
between V
DD and VSS. If the input voltage exceeds this
range by greater than 0.3V (either direction), one of the
diodes becomes forward biased, which may damage
the device if the input current specification is exceeded.
An external RC filter is sometimes added for anti-
aliasing of the input signal. The R component should be
selected to ensure that the sampling time requirements
are satisfied. Any external components connected (via
high impedance) to an analog input pin (capacitor,
zener diode, etc.) should have very little leakage
current at the pin.
RAM Contents: d11 d10 d09 d08 d07 d06 d05 d04 d03 d02 d01 d00
Read to Bus:
Signed Fractional d11
d10d09d08d07d06d05d04d03d02d01d000000
Fractional d11d10d09d08d07d06d05d04d03d02d01d000000
Signed Integer d11
d11 d11 d11 d11 d10d09d08d07d06d05d04d03d02d01d00
Integer 0000d11d10d09d08d07d06d05d04d03d02d01d00