CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Output Ports)

Note: • Be aware that the output terminal is fixed at a low (VSS) level the same as the DC output if "0" is written to the R00–R03 and R10–R13 registers when the special output has been selected.

•Be aware that the output terminal shifts into high impedance status when "1" is written to the high impedance control register (R00HIZ–R03HIZ, R10HIZ–R13HIZ).

•A hazard may occur when the special output signal is turned ON and OFF by software.

•XBZ (R00)

The R00 terminal can output an XBZ signal.

The XBZ signal is the buzzer inverted signal that is output from the sound generator, and can be used to drive a piezoelectric buzzer with the BZ signal.

To output the XBZ signal, set the R00 port as the XBZ output by writing "1" to the XBZOUT register and fix the R00 register at "1" and the R00HIZ register at "0". Use the BZE register for controlling (ON/OFF) the XBZ signal output.

Refer to Section 4.12, "Sound Generator" for details of the buzzer signal and controlling method.

•BZ (R01)

The R01 terminal can output a BZ signal.

The BZ signal is the buzzer signal that is output from the sound generator.

To output the BZ signal, set the R01 port as the BZ output by writing "1" to the BZOUT register and fix the R01 register at "1" and the R01HIZ register at "0". Use the BZE register for controlling (ON/OFF) the BZ signal output.

Refer to Section 4.12, "Sound Generator" for details of the buzzer signal and controlling method.

•TOUT (R02)

The R02 terminal can output a TOUT signal.

The TOUT signal is the clock that is output from the programmable timer, and can be used to provide a clock signal to an external device.

To output the TOUT signal, fix the R02 register at "1" and the R02HIZ register at "0", and turn the signal ON and OFF using the PTOUT register. It is, however, necessary to control the programmable timer.

Refer to Section 4.10, "Programmable Timer" for details of the TOUT signal and controlling method.

•FOUT (R03)

The R03 terminal can output an FOUT signal.

The FOUT signal is a clock (fOSC1 or fOSC3) that is output from the oscillation circuit or a clock that the fOSC1 clock has divided in the internal circuit, and can be used to provide a clock signal to an external device.

To output the FOUT signal, fix the R03 register at "1" and the R03HIZ register at "0", and turn the signal ON and OFF using the FOUTE register.

The frequency of the output clock may be selected from among 4 types shown in Table 4.5.4.2 by setting the FOFQ0 and FOFQ1 registers.

Table 4.5.4.2 FOUT clock frequency

FOFQ1

FOFQ0

Clock frequency

1

1

fOSC3

1

0

fOSC1

0

1

fOSC1 ⋅

1/8

0

0

fOSC1 ⋅

1/64

 

 

 

 

fOSC1: Clock that is output from the OSC1 oscillation circuit

fOSC3: Clock that is output from the OSC3 oscillation circuit

When fOSC3 is selected for the FOUT signal frequency, it is necessary to control the OSC3 oscillation circuit before output.

Refer to Section 4.3, "Oscillation Circuit", for the control and notes. Figure 4.5.4.2 shows the output waveform of the FOUT signal.

S1C63558 TECHNICAL MANUAL

EPSON

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