Hello

I have a one shot timer that I want to start multiple times on my demands in software. I have the following setup

For TopDesign see attach picture.

The isr code:

 Timer_1_ReadStatusRegister();
/* Set the flag variable */
toggle_flag = 1;

the main code:

CyGlobalIntEnable; /* Uncomment this line to enable global interrupts. */

isr_1_Start();
Timer_1_Start();

for(;;)
{
if(toggle_flag == 1)
{
toggle_flag = 0;
Timer_1_Start();
}
}

But it will only goes into the isr once (because it is a one shot timer). How do I get it to go into the isr multiple time? what did I do wrong?

An other thing in the datasheet for the timer it state the following but it does make complete sence to me can anyone explain?

"Note In order to be sure that One Shot mode does not start prematurely, you should use a

Trigger Mode to control the start time, or use some form of software enable mode (Software

Only or Software and Hardware)."

Martin 

Timer_Start() will not reset the timer! You'll need to use the reset terminal (I used additionally a control-register and toggled a bit).

Keep in mind that the reset is NOT asynchronus, so you'll need an additional FF to sync with the input-clock.

Bob

Thx you.

Before I posted this thread I did try to use a control reg with an asynchronous reset that didt work, but that didt work. I will tried you suggestion soon.

When you have any troubles with your project it is much easier for us to have a look at when you upload the complete project here.

To do so:in Developer 5.2:  Build -> Clean Project

then Zip (NOT Raw!) the complete folder and upload it here.

Bob

Hi mtraedholm,

You can also try using the "Trigger Mode" as Rising edge or falling edge to trigger a shot.

After the trigger, the component will require a reset.

Look at the schematic below:

You can use the Terminal Count output of the Timer and OR it with "Low" to trigger a reset after every trigger ends. Hence, your next trigger will respond again. This will eliminate the requirement of manually resetting the Timer everytime.

To trigger, you can make a control register drive high and low (for rising or falling edge trigger). In this case, there is no necessity to use interrupt terminal, hence "Interrupt on TC" should be disabled.

Hi Bob,

Thanks for the suggestion.

My bad, I tested the project by using large delays (in order of ms) and it didn't mis-trigger.