Renesas 4514 Network Card User Manual


 
APPLICATION
2.3 Timers
2-36
4513/4514 Group User’s Manual
Fig. 2.3.7 Timer start by external input setting example (1)
0
b3 b0
Disable Interrupts
Timer 1 interrupt is temporarily disabled.
Interrupt enable flag INTE
Interrupt control register V1
“0”
✕✕
All interrupts disabled (DI instruction)
Timer 1 interrupt occurrence disabled
(TV1A instruction)
INT0 interrupt occurrence disabled
0
b3 b0
00
Stop Timer Operation
Timer 1 and prescaler are temporarily stopped.
Dividing ratio of prescaler is selected.
Timer control register W1
Timer 1 stop (TW1A instruction)
Prescaler stop
Prescaler divided by 4 selected
0
Set Timer Value
Timer 1 count time is set.
Timer 1 reload register R1
“52
16
Timer count value 82 set (T1AB instruction)
b3 b0
1
Set Port
P3
0
/INT0 pin is set to INT0 input.
Port P3
0
output latch
INT0 input set (OP3A instruction)
b3 b0
1
Set Valid Waveform
Valid waveform of INT0 pin is selected. Timer 1 control is enabled.
Interrupt control register I1
Rising edge detected (TI1A instruction)
10
g0 h
Clear Interrupt Request
Timer 1 interrupt activated condition is cleared.
INT0 interrupt activated condition is cleared.
Timer 1 interrupt request flag T1F
INT0 interrupt request flag EXF0
“0”
Timer 1 interrupt activated condition cleared
(SNZT1 instruction)
INT0 interrupt activated condition cleared
(SNZ0 instruction)
“0”
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.
b3 b0
1
Enable Interrupts
The timer 1 interrupt which is temporarily disabled is enabled.
Interrupt control register V1
Interrupt enable flag INTE
“1”
Timer 1 interrupt occurrence enabled
(TV1A instruction)
All interrupts enabled (EI instruction)
✕✕
Timer start by external input
”: it can be “0” or “1.”