DS_1217F_002
73S1217F Data Sheet
1.7.11 Analog Voltage Comparator
The 73S1217F includes a programmable comparator that is connected to the ANA_IN pin. The
comparator can be configured to trigger an interrupt if the input voltage rises above or falls below a
selectable threshold voltage. The comparator control register should not be modified when the analog
interrupt (ANAIEN bit in the INT6Ctl register) is enabled to guard against any false interrupt that might be
generated when modifying the threshold. The comparator has a built-in hysteresis to prevent the
comparator from repeatedly responding to low-amplitude noise. This hysteresis is approximately 20mV.
The maximum voltage on the ANA_IN pad should be less than 3 volts. An external resistor divider is
required for detecting voltages greater than 3.0 volts. Interrupt control is handled in the INT6Ctl register.
Analog Compare Control Register (ACOMP): 0xFFD0 Å 0x00
Table 59: The ACOMP Register
MSB
ANALVL
LSB
–
ONCHG CPOL CMPEN
0
TSEL.1 TSEL.0
Bit
Symbol
Function
When read, indicates whether the input level is above or below the
threshold. This is a real time value and is not latched, so it may change
from the time of the interrupt trigger until read.
ACOMP.7
ANALVL
ACOMP.6
ACOMP.5
–
If set, the Ana_interrupt is invoked on any change above or below the
threshold, bit 4 is ignored.
ONCHG
If set = 1, Ana_interrupt is invoked when signal rises above selected
threshold. If set = 0, Ana_interrupt is invoked when signal goes below
selected threshold (default).
ACOMP.4
CPOL
Enables power to the analog comparator. 1= Enabled. 0 = Disabled
(default).
ACOMP.3
ACOMP.2
CMPEN
0
This value must be fixed at 0.
Sets the voltage threshold for comparison to the voltage on pin ANA_IN.
Thresholds are as follows:
00 = 1.00V
01 = 1.24V
10 = 1.40V
ACOMP.1
ACOMP.0
TSEL.1
TSEL.0
11 = 1.50V
Rev. 1.2
57
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
