ELAN Home Systems EM78P459AK manual Programming the Related Registers, Comparator Outputs

EM78P458/459

OTP ROM

ComparatorX ( Comparator 1 and Comparator 2 ): To reset TMRX while a match occurs and the

TMRXIF flag is set at the same time.

3. Programming the Related Registers

When defining TMRX, refer to the related registers of its operation as shown in Table 9.It must be noted that the PWMX bits must be disabled if their related TMRXs are employed. That is, bit 7 and bit 6 of the PWMCON register must be set to ‘0’.

Table 10 Related Control Registers of TMR1 and TMR2

Address	Name	Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
IOC51	PWMCON/IOC51	PWM2E	PWM1E	T2EN	T1EN	T2P1	T2P0	T1P1	T1P0

4.Timer programming procedures/steps

(1)Load PRDX with the TIMER period.

(2)Enable interrupt function by writing IOCF0, if required

(3)Load a desired value to PWMCON with the TMRX prescaler value and enable both TMRX and disable PWMX.

4.10Comparator

EM78P458/459 has one comparator, which has two analog inputs and one output. The comparator can be employed to wake up from the sleep mode. Fig. 16 shows the circuit of the comparator.

Cin- -

CMP

Cin+ +

CO

Fig. 16 Comparator Operating Mode

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.

•The reference signal must be between Vss and Vdd.

•The reference voltage can be applied to either pi of comparator.

•Threshold detector applications may be of the same reference.

•The comparator can operate from the same or different reference source.

2.Comparator Outputs

This specification is subject to change without prior notice. 41 07.01.2003 (V1.3)