EM78459AM datasheet(44/62 Pages) EMC

44 / 62 page

EM78458/459

8-Bit Microcontroller with MASK ROM

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Product Specification (V1.4) 05.27.2005

(This specification is subject to change without further notice)

4.10.2

Comparator Outputs

The compared result is stored in the CMPOUT of R3.

The comparator outputs is output to P57 by programming bit5<COE> of the

AD-CMPCON register to 1.

P57 must be defined as an output if implemented as the comparator output.

Fig. 17 shows the comparator output block diagram.

To C0

To CPIF

To CMPOUT

CMRD

From other

comparator

RESET

From OP I/O

Fig. 17 The Output Configuration of a Comparator

4.10.3

Using as An Operation Amplifier

The comparator can be used as an operation amplifier if a feedback resistor is

connected from the input to the output externally. In this case, the Schmitt trigger can

be disabled for power saving by setting CE to 1 and COE to 0.

4.10.4

Interrupt

CMPIE (IOCF0.6) must be enabled.

Interrupt occurs at the rising edge of the comparator output pin.

The actual change on the pin can be determined by reading the Bit CMPOUT,

R3<7>.

CMPIF (RF.6), the comparator interrupt flag, can only be cleared by software.

EM78459AM Datasheet(PDF) 44 Page - ELAN Microelectronics Corp