pc87591l-n05 National Semiconductor Corporation, pc87591l-n05 Datasheet - Page 197

• Manufacturer Part Number: pc87591l-n05
• Description: Lpc Mobile Embedded Controller
• Manufacturer: National Semiconductor Corporation

Revision 1.2
4.0 Embedded Controller Modules
4.14 ANALOG COMPARATORS MONITOR (ACM)
The Analog Comparators Monitor (ACM) checks the voltage level of eight analog inputs and reports their values to the core.
The ACM can either measure the voltage of each input with 6-bit resolution or compare the level of all eight inputs with a
programmable threshold.
An operation burst includes either the voltage measurement of all inputs or one comparison check of all inputs to a fixed
threshold. The bursts may be triggered by a low-frequency clock for periodic operation.
4.14.1 Features
4.14.2 Functional Description
Inputs. The ACM has eight analog inputs with a voltage ranging from 0V to V
The voltage level at each input is compared with a reference level, generated by a 6-bit D/A converter.
Operation. The ACM can be operated in one of three modes:
Timing. When the PC87591L-N05 is in Active or Active Executing Wait mode, ACM module timing is based on the core do-
main clock (CLK). When the PC87591L-N05 is in Idle mode, timing is based on the low frequency clock (LFCLK) to minimize
power consumption.
• Voltage measurement
• Comparison check
• Ratiometric measurement using V
• Digital reading output
• 170 s voltage measurement of all the inputs
• Polling- or interrupt-driven interface
• Power consumption
• Voltage Level Burst mode - The reference level generated by the D/A converter is ramped from 0V to FS by incre-
• Threshold Comparison Burst mode - A programmable value is loaded into the D/A converter, generating a constant
• Low Power Threshold Comparison mode - The inputs are periodically compared with a fixed threshold. The compar-
— Eight analog inputs
— 6-bit resolution
— 0V to V
— High-impedance inputs
— 6-bit threshold resolution
— Simultaneous on all inputs
— Eight buffers for voltage value
— One buffer for comparison check
— Zero current when disabled
— Low average current in Idle mode
menting the value loaded into the converter. Whenever the ramp crosses the level of an input, its comparator toggles
state, and the D/A loaded value is latched into the corresponding Voltage Level Buffer. At the end of the ramp, exe-
cution stops and a set of eight voltage level values (one per input) is available.
threshold level. A bit is set for each input if the input’s voltage level is higher than the threshold. At the end of the
single comparison, the Comparison Result register holds the status of the eight inputs.
ison is triggered by a low rate signal from the TWD module (T0IN). In addition, an interrupt is generated if at least
one input is below (or above) the threshold.
CC
Full Scale (FS) input voltage range
CC
(Continued)
197
CC
(FS), as shown in Figure 71.
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