W741L250 Datasheet, PDF (14/86 Pages) Winbond – 4-BIT MICROCONTROLLER

W741L250
Hold Mode Operation
In hold mode, all operations of the µC cease, except for the operation of the oscillator, timer, and
LCD driver. The µC enters hold mode when the HOLD instruction is executed. The hold mode can be
released in one of five ways: by the action of Timer 0, Timer 1, Divider 0, the INT pin, or the RC port.
Before the device enters the hold mode, the HEF, PEF, and IEF flags must be set to define the hold
mode release conditions. For more details, refer to the instruction-set table and the following flow
chart.
Divider 0, Timer 0, Timer 1
INT, Signal Change on
Port RC
Yes
Interrupt
Enable?
Yes
IEF
Flag Set?
Yes
No
No
In
No
HOLD
Mode?
No
Interrupt
Enable?
Yes
IEF
No
Flag Set?
Yes
Reset EVF.n Flag
Execute
Interrupt Service Routine
HEF
Flag Set?
Reset EVF.n Flag
Execute
Interrupt Service Routine
(Note)
No
Yes
(Note)
Disable interrupt
Disable interrupt
HOLD
Note : The bit of EVF corresponding to the interrupt request signal will be reset.
PC <- (PC+1)
Figure 8. Hold Mode and Interrupt Operation Flow Chart
- 14 -