4513_03 Datasheet, PDF (139/210 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.3 Timers
ΠDisable Interrupts
Timer 1 interrupt is temporarily disabled.
Interrupt enable flag INTE
Interrupt control register V1
“0”
All interrupts disabled (DI instruction)
b3
b0
! 0 ! 0 Timer 1 interrupt occurrence disabled
(TV1A instruction)
INT0 interrupt occurrence disabled
 Stop Timer Operation
Timer 1 and prescaler are temporarily stopped.
Dividing ratio of prescaler is selected.
Timer control register W1
b3
0
0
0
b0
!
Timer 1 stop (TW1A instruction)
Prescaler stop
Prescaler divided by 4 selected
Ž Set Timer Value
Timer 1 count time is set.
Timer 1 reload register R1 “5216”
Timer count value 82 set (T1AB instruction)
 Set Port
P30/INT0 pin is set to INT0 input.
Port P30 output latch
b3
b0
! !! 1
INT0 input set (OP3A instruction)
 Set Valid Waveform
Valid waveform of INT0 pin is selected. Timer 1 control is enabled.
b3
b0
Interrupt control register I1 ! 1 0 1 Rising edge detected (TI1A instruction)
‘ Clear Interrupt Request
Timer 1 interrupt activated condition is cleared.
INT0 interrupt activated condition is cleared_g._{0 h}
Timer 1 interrupt request flag T1F “0”
INT0 interrupt request flag EXF0 _{“0”}
Timer 1 interrupt activated condition cleared
(SNZT1 instruction)
INT0 interrupt activated condition cleared
(SNZ0 instruction)
Note when the interrupt request is cleared
When ‘ is executed, considering the skip of the next instruction according to the
interrupt request flags T1F and EXF0, insert the NOP instruction after the SNZT1
and SNZ0 instructions.
’ Enable Interrupts
The timer 1 interrupt which is temporarily disabled is enabled.
Interrupt control register V1
b3
b0
! 1!!
Timer 1 interrupt occurrence enabled
(TV1A instruction)
Interrupt enable flag INTE “1”
All interrupts enabled (EI instruction)
Timer start by external input
“!”: it can be “0” or “1.”
Fig. 2.3.7 Timer start by external input setting example (1)
2-36
4513/4514 Group User’s Manual