NEC PD750008 - Manual (Page 242)

222
µPD750008 USER'S MANUAL
(2) Application of the HALT mode (at f
X
= 4.19 MHz)
<Intermittent operation under the following conditions>
• The main system clock is switched to the subsystem clock on the falling edge of INT4.
• The oscillation of the main system clock is stopped, and HALT mode is set.
• In the standby mode, intermittent operation is performed at intervals of 0.5 s.
• The subsystem clock is switched back to the main system clock on the rising edge of INT4.
• INTBT is not used.
<Timing chart>
INT4
INT4
250 ms
Operating mode
(low-speed)
Intermittent operation
(HALT mode + low-speed operation)
Operating mode
V
DD
0 V
P00/INT4
CPU operation
Voltage on V
DD
Operating mode
(high-speed)