Fig. 2.2.8 Timer 4 Constant Period Interrupt Setting Example - Renesas 4513 User Manual

APPLICATION
2.2 Interrupts
Disable Interrupts
Timer 4 interrupt is temporarily disabled.
Stop Timer Operation
Timer 4, timer 3 and prescaler are temporarily stopped.
Dividing ratio of prescaler is selected.
Set Timer Value
Timer 3 and timer 4 count times are set. (The formula is shown
Clear Interrupt Request
Timer 4 interrupt activated condition is cleared.
Timer 4 interrupt request flag T4F "0"
Note when the interrupt request is cleared
When
interrupt request flag T4F, insert the NOP instruction after the SNZT4 instruction.
Start Timer 4 Operation
Timer 4, timer 3 and prescaler temporarily stopped are restarted.
Enable Interrupts
The timer 4 interrupt which is temporarily disabled is enabled.
A The prescaler dividing ratio, time 3 count value and timer 4 count value to make the interrupt occur
every 250 ms are set as follows.
250 ms
" ": it can be "0" or "1."

Fig. 2.2.8 Timer 4 constant period interrupt setting example

2-24
Interrupt enable flag INTE
Interrupt control register V2
Timer control register W1
Timer control register W3
Timer control register W4
Timer 3 reload register R3
Timer 4 reload register R4
is executed, considering the skip of the next instruction according to the
b3
1
Timer control register W4
b3
Timer control register W3
1
b3
Timer control register W1 1 1
Interrupt control register V2
Interrupt enable flag INTE
Constant period interrupt execution start
–1
(4.0 MHz) 3
System clock Instruction Prescaler
clock dividing
ratio
4513/4514 Group User's Manual
"0" All interrupts disabled (DI instruction)
b3 b0
Timer 4 interrupt occurrence disabled
0
(TV2A instruction)
b3 b0
Prescaler stop (TW1A instruction)
0 1
Prescaler divided by 16 selected
b3 b0
Timer 3 stop (TW3A instruction)
0 0 1
Prescaler selected for count source
b3 b0
Timer 4 stop (TW4A instruction)
0 0 0
Timer 3 underflow signal selected for count source
"52 "
16 Timer count value 82 set (T3AB instruction)
"F9 "
16 Timer count value 249 set (T4AB instruction)
Timer 4 interrupt activated condition cleared
(SNZT4 instruction)
b0
0 0 Timer 4 operation start (TW4A instruction)
b0
0 1 Timer 3 operation start (TW3A instruction)
b0
Prescaler operation start (TW1A instruction)
b3 b0
Timer 4 interrupt occurrence enabled
1
(TV2A instruction)
"1" All interrupts enabled (EI instruction)
16 (82+1) (249+1)
Timer 3 Timer 4
count count
value value
A below.)