NEC 78014Y Series, User Manual

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CHAPTER 12 CLOCK OUTPUT CONTROL CIRCUIT
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CHAPTER 12 CLOCK OUTPUT CONTROL CIRCUIT
12.1 Clock Output Control Circuit Functions
The clock output control circuit is intended for carrier output during remote controlled transmission and clock output
for supply to peripheral LSI. Clocks selected with the timer clock select register 0 (TCL0) are output from the PCL/
P35 pin.
Follow the procedure below to output clock pulses.
(1) Select the clock pulse output frequency (with clock pulse output disabled) with bits 0 to 3 (TCL00 to TCL03)
of TCL0.
(2) Set the P35 output latch to 0.
(3) Set bit 5 (PM35) of port mode register 3 (PM3) to 0 (set to output mode).
(4) Set bit 7 (CLOE) of TCL0 to 1.
Caution Clock output cannot be used if P35 output latch is set to 1.
Remark When clock output enable/disable is switched, the clock output control circuit does not output pulses with
small widths (See the mark
*
in Figure 12-1).
Figure 12-1. Remote Controlled Output Application Example
CLOE
PCL/P35
Pin Output
* *