W741E20X Datasheet, PDF (23/84 Pages) Winbond – 4-BIT FLASH MICROCONTROLLER

Preliminary W741E20X
Continued
R7 R6
R5
R4
R3
R2
R1
R0 FUNCTION
0
0
0
0
0
0 4096 Hz
0
0
0
0
0
1 4096 Hz * 128 Hz
0
0
0
0
1
0 4096 Hz * 64 Hz
11
0
0
0
1
0
0 4096 Hz * 8 Hz
0
0
1
0
0
0 4096 Hz * 4 Hz
0
1
0
0
0
0 4096 Hz * 2 Hz
1
0
0
0
0
0 4096 Hz * 1 Hz
Interrupts
The W741E20X provides five internal interrupt sources (Divider 0, Timer 0, Timer 1, serial I/O) and two
external interrupt sources ( INT , port RC). Vector addresses for each of the interrupts are located in
the range of program memory (ROM) addresses 004H to 020H. The flags IEF, PEF, and EVF are used
to control the interrupts. When EVF is set to "1" by hardware and the corresponding bits of IEF and
PEF have been set by software, an interrupt is generated. When an interrupt occurs, all of the
interrupts are inhibited until the EN INT or MOV IEF, #I instruction is invoked. The interrupts can also
be disabled by executing the DIS INT instruction. When an interrupt is generated in hold mode, the
hold mode will be released momentarily and 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 14. The control diagram is shown below.
Divider 0
overflow signal
Timer 0
underflow signal
Timer 1
underflow signal
SQ
R
SQ
R
SQ
R
EN INT
MOV IEF,#I
EVF.0
Initial Reset
IEF.0
EVF.1
IEF.1
EVF.7
IEF.7
Enable
Interrupt
Process
Circuit
Interrupt
Vector
Generator
004H
008H
020H
Initial Reset
Disable
CLR EVF,#I instruction
Figure 13. Interrupt event control diagram
DIS INT instruction
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Publication Release Date: March 1998
Revision A1