73S1215F Maxim, 73S1215F Datasheet - Page 55

• Manufacturer Part Number: 73S1215F
• Description: The Teridian 73S1215F is a self-contained SoC smart card reader IC that is an ideal solution for any USB-connected ISO 7816 design
• Manufacturer: Maxim

DS_1215F_003
1.7.9
The 73S1215F 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
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
Analog Compare Control Register (ACOMP): 0xFFD0
Rev. 1.4
ACOMP.7
ACOMP.6
ACOMP.5
ACOMP.4
ACOMP.3
ACOMP.2
ACOMP.1
ACOMP.0
Bit
Analog Voltage Comparator
MSB
ANALVL
ANALVL
ONCHG
Symbol
CMPEN
TSEL.1
TSEL.0
CPOL
–
0
–
INT6Ctl
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.
If set, the Ana_interrupt is invoked on any change above or below the
threshold, bit 4 is ignored.
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).
Enables power to the analog comparator. 1= Enabled. 0 = Disabled
(default).
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
11 = 1.50V
ONCHG
register) is enabled to guard against any false interrupt that might be
Table 60: The ACOMP Register
CPOL
CMPEN
0x00
Function
0
TSEL.1 TSEL.0
73S1215F Data Sheet
LSB
INT6Ctl
register.
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