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:
- 5:9be3080ca8ba
- Parent:
- 4:64d9c0bed75b
- Child:
- 6:7f90a61e1a69
--- a/main.cpp Mon Jun 03 15:04:08 2013 +0000
+++ b/main.cpp Tue Jun 04 06:14:19 2013 +0000
@@ -4,14 +4,14 @@
#define CONV_KILO_OHM 0.0072 //if use 0.1 micro F
#define IN_TIMES 10 //interrupt times
#define READ_TIMER 3 //rest times when reads timer
-#define WAIT_IN 200 //wait interrupts in msec
-#define WAIT_NEXT 4800 //wait next measurement in msec
+#define WAIT_IN 1000 //wait interrupts in msec
+#define WAIT_NEXT 4000 //wait next measurement in msec
#define MAX_INTERVAL 100000 // > 0.1 sec ( < 10 Hz) in microseconds
#define MIN_INTERVAL 20 // < 20 micro sec ( > 50 kHz) in microseconds
#define ONESEC_BY_MICRO 1000000// 1 sec in microseconds
InterruptIn in(p8); //connect to the Discharge of 555
-DigitalOut run555(p9);//connect to the Reset of 555
+DigitalOut run555(p9);//connect to the Reset of 555
DigitalOut led(LED1);
Timer t1;
@@ -29,7 +29,7 @@
t1.reset();// Reset timer and wait for next interrupt
rest_in--;
}
-
+
if(rest_in == 0){
//No use interrupt
run555 = led = 0;
@@ -39,11 +39,12 @@
int main() {
run555 = led = 0;
+ // Set up the interrupt
in.mode(PullUp);
- in.rise(&flip);// Set up the interrupt for rising edge
+ in.fall(&flip);
printf("\rStarting measure\n");
-
+
while (1) {
//Use interrupt
my_interval = 0;