Satoru Yoshida
test interruptIn feature with 555 timer
Dependencies: ClockControl PowerControl mbed
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Frequency_counter
by 
Satoru Yoshida
Test interruptIn function with using LMC555 timer IC
LPC 1768 自身が持つタイマー割り込み機能を使わずに、 あえて外部のタイマー IC 555 からの信号で周期的に割り込みするテスト。
下記の回路例では、555 の output 端子が 約 10 秒周期のうち、0.3 秒間 Low になるはず。 ただし、コンデンサーおよび抵抗の誤差の影響があり、実測値は約７秒周期
C を 47μ から 330 μ に変えると約１分前後で周期的に割り込みがかかります。
なるべく配線が交差しないように部品配置してみた例
Diff: main.cpp
- Revision:
- 7:42e7f18361c8
- Parent:
- 6:7f90a61e1a69
- Child:
- 8:cb966096a916
--- a/main.cpp Sun Aug 11 08:34:00 2013 +0000
+++ b/main.cpp Wed Nov 06 07:38:20 2013 +0000
@@ -4,7 +4,8 @@
InterruptIn in(p8); //connect to the Discharge of 555
DigitalOut run555(p9);//connect to the Reset of 555
-DigitalOut led(LED1);
+DigitalOut led1(LED1);//running 555
+DigitalOut led2(LED2);//not ready
Timer t1;
float my_interval = 0;//between interrupts in microseconds
@@ -23,13 +24,13 @@
if(rest_in <= 0){
//No use interrupt
- run555 = led = 0;
+ run555 = led1 = 0;
t1.stop();
}
}
int main() {
- run555 = led = 0;
+ run555 = led1 = led2 = 0;
// Set up the interrupt
in.mode(PullUp);
in.rise(&flip);
@@ -41,12 +42,14 @@
my_interval = 0;
t1.start();
rest_in = IN_TIMES;
- run555 = led = 1;
+ run555 = led1 = 1;
+ led2 = 0;
wait_ms(WAIT_IN);
- run555 = led = 0;//force stop
+ run555 = led1 = 0;//force stop
if (my_interval < MIN_INTERVAL || my_interval > MAX_INTERVAL){
printf("\r not ready\n");
+ led2 = 1;
} else {
my_freq = ONESEC_BY_MICRO / my_interval; // Convert to Hz
my_ohm = my_interval * CONV_KILO_OHM;// Convert to kilo ohm