Question

I know that if we want to display the pc time, we will use the below coding:

   System.Windows.Forms.Timer tmr = null;
    private void StartTimer()
    {
        tmr = new System.Windows.Forms.Timer();
        tmr.Interval = 1000;
        tmr.Tick += new EventHandler(tmr_Tick);
        tmr.Enabled = true;
    }

    void tmr_Tick(object sender, EventArgs e)
    {
        textBox6.Text = DateTime.Now.ToString("dd/MM/yy HH:mm:ss");
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        StartTimer();
    }

But I do not want to display the pc time. I want to display another time (the rtc time from microcontroller for my case).

If I get the rtc time from serial port and displayed into the text box as “09:00:00”. It is just static there right? How do I get it to run/increment on the text box?

I’ve tried the below which I modified from above coding:

    System.Windows.Forms.Timer rtc = null;
    private void StartRTC()
    {
        rtc = new System.Windows.Forms.Timer();
        rtc.Interval = 1000;
        rtc.Tick += new EventHandler(rtc_Tick);
        rtc.Enabled = true;
    }
    int i = 1;
    DateTime dt = new DateTime();
    void rtc_Tick(object sender, EventArgs e)
    {
        textBox17.Text = dt.AddSeconds(i).ToString("HH:mm:ss");
        i++;
    }

But the time showed on my text box always start increment on 00:00:00.

How do I let it to start increment on the time I get from my microcontroller rtc?

Answer 1

That’s because you’re starting with new DateTime() and so you’re getting and default value of a new DateTime class. You should initialize the value of the DateTime with the API call to the microprocessor.

Example

Please note because I know nothing about the API for your microprocessor I can only write psuedo-code. In your second example, replace the following line…

DateTime dt = new DateTime();

with…

DateTime dt = DateTime.Parse({some microprocessor API call for the RTC value});

Edited based off of last comment

System.Windows.Forms.Timer rtc = null; 
DateTime dt;  // NOTE I DON'T INITIALIZE THIS TO ANYTHING AT FIRST

private void StartRTC() 
{ 
    rtc = new System.Windows.Forms.Timer(); 
    rtc.Interval = 1000; 
    rtc.Tick += new EventHandler(rtc_Tick); 
} 

void rtc_Tick(object sender, EventArgs e) 
{ 
    // NOTE I GOT RID OF i - THAT WASN'T GOING TO WORK LIKE THAT 
    // YOU JUST WANT TO ADD ONE SECOND BECAUSE THE TIMER TICKS EVERY SECOND:
    textBox17.Text = dt.AddSeconds(1).ToString("HH:mm:ss");

    dt = DateTime.Parse(textBox17.Text);
}

 // I HAVE NO IDEA WHAT YOUR METHOD HANDLER IS CALLED, THIS IS 
 // JUST FOR THE EXAMPLE
void buttonSetRtc_Click(object sender, EventArgs e)  
{
    // HERE IS YOUR CALL TO THE MICROCONTROLLER FOR THE INITIAL TIME:
    textBox17.Text = {some call to the microcontroller};  
    dt = DateTime.Parse(textBox17.Text);  // NOW THIS LINE WON'T FAIL
    rtc.Enabled = true;  // NOTE I MOVED THIS LINE TO KEEP IT FROM FAILING
}