em78f644nso28s ELAN Microelectronics Corp, em78f644nso28s Datasheet - Page 125

• Manufacturer Part Number: em78f644nso28s
• Description: Flash Series 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.0) 05.05.2010
(This specification is subject to change without further notice)
6.10 Comparator
EM78F664N/F662N/F661N/F564N/F562N/F561N has one comparator; while
F648N/F548N has two comparators. Each one has two analog inputs and one
output. The comparators can be utilized to Wake up the MCU from Sleep mode. The
following figure illustrates the comparator circuit and operation mode.
6.10.1 External Reference Signal
The analog signal that is presented at CIN- compares to the signal at CIN+, and the
digital output (CO) of the comparator is adjusted accordingly.
6.10.2 Internal Reference Signal
EM78F648N/F548N offers two internal voltage references which are applicable to
CIN1+/CIN2+. You can use the voltage references in setting C1RS of R39 Bank
0/C2RS of R3C Bank 0 and corresponding voltage level in R43 Bank 0.
Threshold detector applications may use the same reference.
The comparator can operate from the same or different reference source.
The reference signal must be between VSS and VDD.
The reference voltage can be applied to either pin of the comparator.
CIN+
CIN-
Figure 6-22 Comparator Circuit and Operation Mode
CIN+
CIN-
CO
10mV
EM78F648/644/642/641/548/544/542/541N
10mV
+
-
CMP
8-Bit Microcontroller
CO
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