EM78P458AP datasheet(42/76 Pages) EMC

42 / 76 page

EM78P458/459

OTP ROM

• 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

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. 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.

5. Wake-up from SLEEP Mode

• If enabled, the comparator remains active and the interrupt remains functional, even under SLEEP

mode.

• If a mismatch occurs, the interrupt will wake up the device from SLEEP mode.

• The power consumption should be taken into consideration for the benefit of energy conservation.

• If the function is unemployed during SLEEP mode, turn off comparator before entering into sleep

mode.

This specification is subject to change without prior notice.

06.25.2004 (V1.4)

EM78P458AP Datasheet(PDF) 42 Page - ELAN Microelectronics Corp