working terminal toggle of PWM

hod4_uart_b/main.cpp

@@ -0,0 +1,56 @@
+// main.cpp
+#include "mbed.h"
+
+#define MAXIMUM_BUFFER_SIZE 32
+
+PwmOut led_pwm(LED1);
+DigitalIn  button(PC_13);
+
+static BufferedSerial serial_port(USBTX, USBRX);
+
+int press_duty(int num_presses) {
+    if (num_presses > 10) {
+        num_presses = 0;
+    }
+    num_presses += 1;
+
+    return num_presses;
+}
+
+int main()
+{
+    serial_port.set_baud(9600);
+    serial_port.set_format(
+        /* bits */ 8,
+        /* parity */ BufferedSerial::None,
+        /* stop bit */ 1
+    );
+
+    char buf[MAXIMUM_BUFFER_SIZE] = {0};
+    char msg[64];
+
+    int num_presses = 1;
+    float strieda = 0.0f;
+    led_pwm.period(0.02f);
+    led_pwm.write(0.50f);
+    while (1) {
+        float strieda = 0;
+
+        if (uint32_t num = serial_port.read(buf, sizeof(buf))) {
+          strieda = press_duty(num_presses)/10.0;
+          led_pwm.write(strieda);
+          int len = snprintf(msg, sizeof(msg), "strieda = %.3f\r\n", strieda);
+          // serial_port.write(buf, len);
+
+          // Echo the input back to the terminal.
+          serial_port.write(buf, strieda);
+
+          num_presses = press_duty(num_presses);
+          while (num == 0) {
+            ThisThread::sleep_for(10ms);
+          }
+        }
+
+        ThisThread::sleep_for(150ms);
+    }
+}