Datasheet

 2011 Microchip Technology Inc. Preliminary DS41576B-page 117
PIC12F752/HV752
FIGURE 14-2: VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE
14.5 DAC Voltage Reference Output
The DAC output (dac_ref) can be applied to the
DACOUT pin as an unbuffered signal by:
• Setting the DACOE bit of the DACCON0 register
• Clearing the FVRBUFSS bit of the FVRCON
register.
• Clearing the FVRBUFEN bit of the FVRCON
register.
Figure 14-3 shows a block diagram pin configuration
for the dac_ref and fvr_ref signals. This unbuffered
DACOUT pin has limited current drive capability. When
a higher drive current is required, an external buffer can
be used on the DACOUT pin. Figure 14-2 shows an
example of buffering technique.
The DAC output can also be configured to use an inter-
nal buffer by:
• Setting the FVRBUFEN bit of the FVRCON regis-
ter changing the pin configuration to be the
REFOUT pin.
Enabling the DACOUT pin automatically overrides any
digital input or output functions of the pin. Reading the
DACOUT pin when it has been configured for DAC ref-
erence voltage output will always return a ‘0’.
FIGURE 14-3: DAC/FVR OUTPUT PIN
14.6 Operation During Sleep
When the device wakes up from Sleep through an
interrupt or a Watchdog Timer time-out, the contents of
the DACCON0 register are not affected. To minimize
current consumption in Sleep mode, the voltage
reference should be disabled.
14.7 Effects of a Reset
A device Reset clears the DACCON0 and DACCON1
registers. As a result:
• the DAC module is disabled.
• the DAC voltage output is disabled on the
DACOUT pin.
DACOUT
Buffered DAC Output
+
–
DAC
Module
Voltage
Reference
Output
Impedance
R
PIC
®
MCU
REFOUT
DACOUT
fvr_ref
dac_ref
0
1
FVRBUFSS
DACOE
FVRBUFEN
x1