W741L250 Datasheet, PDF (13/86 Pages) Winbond – 4-BIT MICROCONTROLLER

W741L250
be disabled by executing the DIS INT instruction. When an interrupt is generated in hold mode, the
hold mode will be released momentarily and the interrupt subroutine will be executed. After the RTN
instruction is executed in an interrupt subroutine, the µC will enter hold mode again. The operation
flow chart is shown in Figure 8. The control diagram is shown below.
Divider 0
overflow signal
Timer 0
underflow signal
Port RC
signal change
INT pin
falling edge signal
Timer 1
underflow signal
SQ
R
SQ
R
SQ
R
SQ
R
SQ
R
Interrupt Event Control Diagram
Initial Reset
EN INT
MOV IEF, #I
EVF.0
IEF.0
Enable
EVF.1
IEF.1
EVF.2
IEF.2
EVF.4
IEF.4
Interrupt
Process
Circuit
Interrupt
Vector
Generator
EVF.7
IEF.7
004H
008H
00CH
014H
020H
Initial Reset
Disable
CLR EVF, #I instruction
DIS INT instruction
Figure 7. Interrupt Event Control Diagram
Stop Mode Operation
In stop mode, all operations of the µC cease (including the operation of the oscillator). The µC enters
stop mode when the STOP instruction is executed and exits stop mode when an external trigger is
activated (by a low level on the INT pin or a falling signal on the RC port). When the designated
signal is accepted, the µC awakens and executes the next instruction (if the corresponding bits of IEF
and PEF have been set, It will enter the interrupt service routine after stop mode released). To
prevent erroneous execution, the NOP instruction should follow the STOP command.
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Publication Release Date: March 1998
Revision A2