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PULSE OUTPUT PORT MODE
7905 Group User’s Manual Rev.1.0
9-14
9.2 Block description of pulse output port 0
Fig. 9.2.7 Relationship between P6OUTCUT input, waveform output control bit 1, and pulse output pin
9.2.5 Pin P6OUTCUT (pulse-output-cutoff signal input pin)
When a falling edge is input to pin P6OUTCUT, the waveform output control bit 1 (bit 7 at address A616)
becomes “0” and the pulse output pins enter the floating state. (In other words, pulse output becomes
disabled.) The pulse output pins where pulse output is to be inactive depend on the pulse output mode.
Pulse mode 0: RTP00 to RTP03
Pulse mode 1: RTP00 to RTP03, RTP10, RTP11
When restarting pulse output after the pulse output becomes inactive, be sure to return the input level at
pin P6OUTCUT to “H” level; and then, be sure to set the waveform output control bit 1 to “1.” When the input
level at pin P6OUTCUT is “L” level, the waveform output control bit 1 cannot be “1.”
Also, at this time, bits 0 through 7 of the port P6 direction register (address 1016) become “000000002.”
(Refer to section “5.2.4 Pin P6OUTCUT/INT4.”) Therefore, if it is necessary to switch port pins P60 through
P67 to port output pins, be sure to do as follows:
Return the input level at pin P6OUTCUT to “H” level.
Write data to the port P6 register (address E16)’s bits, corresponding to the port P6 pins which will
output data.
Set the port P6 direction register’s bits, corresponding to the port P6 pins in , to “1” in order to set
these port pins to the output mode.
When the input level at pin P6OUTCUT is “L” level, no bit of the port P6 direction register can be “1.”
Figure 9.2.7 shows the relationship between the P6OUTCUT input, waveform output control bit 1, and pulse
output pin.
Note that, when not making the pulse output inactive by using pin P6OUTCUT, be sure to connect pin
P6OUTCUT to Vcc via a resistor.
P6OUTCUT input
Programmable
I/O port
Floating
Waveform output control bit 1
(bit 7 at address A616)
Pulse output pin
Pulse output
Floating
Selection of pulse output port mode
(selected by bit s 3 to 0 at address A616)
When the pulse output port mode is selected, the pulse outpit pins become floating.
The pulse is output by writing of “1” with the input level at pin P6OUTCUT = “H.”
When a falling edge is input to pin P6OUTCUT, this bit becomes “0.”