Datasheet

Table Of Contents
2011-2013 Microchip Technology Inc. DS40001609C-page 139
PIC16(L)F1508/9
15.2 ADC Operation
15.2.1 STARTING A CONVERSION
To enable the ADC module, the ADON bit of the
ADCON0 register must be set to a ‘1’. Setting the GO/
DONE bit of the ADCON0 register to a1’ will start the
Analog-to-Digital conversion.
15.2.2 COMPLETION OF A CONVERSION
When the conversion is complete, the ADC module will:
Clear the GO/DONE
bit
Set the ADIF Interrupt Flag bit
Update the ADRESH and ADRESL registers with
new conversion result
15.2.3 TERMINATING A CONVERSION
If a conversion must be terminated before completion,
the GO/DONE
bit can be cleared in software. The
ADRESH and ADRESL registers will be updated with
the partially complete Analog-to-Digital conversion
sample. Incomplete bits will match the last bit
converted.
15.2.4 ADC OPERATION DURING SLEEP
The ADC module can operate during Sleep. This
requires the ADC clock source to be set to the FRC
option. Performing the ADC conversion during Sleep
can reduce system noise. If the ADC interrupt is
enabled, the device will wake-up from Sleep when the
conversion completes. If the ADC interrupt is disabled,
the ADC module is turned off after the conversion com-
pletes, although the ADON bit remains set.
When the ADC clock source is something other than
FRC, a SLEEP instruction causes the present conver-
sion to be aborted and the ADC module is turned off,
although the ADON bit remains set.
15.2.5 AUTO-CONVERSION TRIGGER
The auto-conversion trigger allows periodic ADC mea-
surements without software intervention. When a rising
edge of the selected source occurs, the GO/DONE bit
is set by hardware.
The auto-conversion trigger source is selected with the
TRIGSEL<3:0> bits of the ADCON2 register.
Using the auto-conversion trigger does not assure
proper ADC timing. It is the user’s responsibility to
ensure that the ADC timing requirements are met.
See Table 15-2 for auto-conversion sources.
Note: The GO/DONE
bit should not be set in the
same instruction that turns on the ADC.
Refer to Section 15.2.6 “ADC Conver-
sion Procedure”.
Note: A device Reset forces all registers to their
Reset state. Thus, the ADC module is
turned off and any pending conversion is
terminated.
TABLE 15-2: AUTO-CONVERSION
SOURCES
Source Peripheral Signal Name
Timer0 T0_overflow
Timer1 T1_overflow
Timer2 T2_match
Comparator C1 C1OUT_sync
Comparator C2 C2OUT_sync
CLC1 LC1_out
CLC2 LC2_out
CLC3 LC3_out
CLC4 LC4_out