DS_1209F_004
73S1209F Data Sheet
1.7.8 Analog Voltage Comparator
The 73S1209F 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.
Interrupt control is handled in the INT6Ctl register.
Analog Compare Control Register (ACOMP): 0xFFD0 Å 0x00
Table 55: The ACOMP Register
MSB
ANALVL
LSB
ONCHG CPOL CMPEN TSEL.2 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
TSEL.2
Sets the voltage threshold for comparison to the voltage on pin
ANA_IN. Thresholds are as follows:
TSEL.2
TSEL.1
TSEL.0 Voltage Threshold
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
1.00V
1.24V
1.40V
1.50V
1.75V
2.00V
2.30V
2.50V
ACOMP.1
ACOMP.0
TSEL.1
TSEL.0
Rev. 1.2
51
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
