1. Enable the analog comparator clock by writing a value of 0x0010.0000 to the RCGC1 register
in the System Control module (see page 254).
2. Enable the clock to the appropriate GPIO modules via the RCGC2 register (see page 263). To
find out which GPIO ports to enable, refer to Table 21-5 on page 948.
3. In the GPIO module, enable the GPIO port/pin associated with the input signals as GPIO inputs.
To determine which GPIO to configure, see Table 21-4 on page 941.
4. Configure the PMCn fields in the GPIOPCTL register to assign the analog comparator output
signals to the appropriate pins (see page 447 and Table 21-5 on page 948).
5. Configure the internal voltage reference to 1.65 V by writing the ACREFCTL register with the
value 0x0000.030C.
6.
Configure the comparator to use the internal voltage reference and to not invert the output by
writing the ACCTLn register with the value of 0x0000.040C.
7. Delay for 10 µs.
8. Read the comparator output value by reading the ACSTATn register’s OVAL value.
Change the level of the comparator negative input signal C- to see the OVAL value change.
17.5 Register Map
Table 17-4 on page 820 lists the comparator registers. The offset listed is a hexadecimal increment
to the register’s address, relative to the Analog Comparator base address of 0x4003.C000. Note
that the analog comparator clock must be enabled before the registers can be programmed (see
page 254). There must be a delay of 3 system clocks after the analog comparator module clock is
enabled before any analog comparator module registers are accessed.
Table 17-4. Analog Comparators Register Map
See
page
DescriptionResetTypeNameOffset
821Analog Comparator Masked Interrupt Status0x0000.0000R/W1CACMIS0x000
822Analog Comparator Raw Interrupt Status0x0000.0000ROACRIS0x004
823Analog Comparator Interrupt Enable0x0000.0000R/WACINTEN0x008
824Analog Comparator Reference Voltage Control0x0000.0000R/WACREFCTL0x010
825Analog Comparator Status 00x0000.0000ROACSTAT00x020
826Analog Comparator Control 00x0000.0000R/WACCTL00x024
825Analog Comparator Status 10x0000.0000ROACSTAT10x040
826Analog Comparator Control 10x0000.0000R/WACCTL10x044
17.6 Register Descriptions
The remainder of this section lists and describes the Analog Comparator registers, in numerical
order by address offset.
July 24, 2012820
Texas Instruments-Production Data
Analog Comparators
OBSOLETE: TI has discontinued production of this device.
