NEC PD754144 - Manual (Page 219)

CHAPTER 8 STANDBY FUNCTION
219 User’s Manual U10676EJ3V0UM
Figure 8-1. Releasing Standby Mode (2/2)
(c) Releasing HALT mode by RESET signal
RESET
signal
Clock
HALT
instruction
Operation
mode
HALT mode
Wait Note
Operation
mode
Oscillates
(d) Releasing HALT mode by interrupt
Standby release
signal
Clock
HALT
instruction
Operation
mode
HALT mode Operation mode
Oscillates
Note
µPD754244: The following two times can be selected by mask option.
2 17 /f X (21.8 ms at 6.0 MHz, 31.3 ms at 4.19 MHz)
2 15 /f X (5.46 ms at 6.0 MHz, 7.81 ms at 4.19 MHz)
µPD754144: The wait time is fixed to 56/f
CC
(56 µs at 1.0 MHz)
Remark The broken lines indicate acknowledgment of the interrupt request that releases the standby mode.
The interrupt used to release STOP mode is selected by setting (1) the corresponding interrupt enable flag (IE).
STOP mode is released when the interrupt request flag (IRQ) selected in STOP mode is set (1).
In this case, be sure to clear (0) all IEs and IRQs before setting (1) the corresponding interrupt IE. This is because
STOP mode is not released by any interrupt other than that selected.
The procedure to release STOP mode by interrupt generation is shown below.
<1> Clear all IEs and IRQs
<2> Set IE for the interrupt used to release STOP mode.