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Hi to all

How can i make a timer interrupt run at a 10us rate so that i can generate times to the nearest 10us.

Thanks,
Wayne

Hiya Wayne
10uS = 1/ 10x10-6 =100KHz
So depending on osc speed, you can use timer 0 or If not using PWM, timer 2 to generate interrupt at that speed (time)
You have a choice of selecting a slightly shorter int time then using format:
count = count + 1
count < a_number
then count = 0: Flag = 1 etc
Or you select a slower int frequency and add tmr0l += a_number; (or tmr0 depending on your target device).

If you want to post a flowchart that is set up for your target chip and osc speed + type of osc.
Then I will see if I can add the 10uS int macro.
10us is very quick, wont leave much time for anything else

Thanks medelec35,

I have not started the project yet just need to get the timer working first then start on the project.
any help would be very grateful.

Wayne

If you let me know target device, osc type. internal external etc and speed. I will create one for you to work with.

medelec35,

I will use a 18F4520 and some thing like a 10Mhz clock.

Thanks
wayne

Here is a version with a 10uS interrupt
Note the higher the osc frequency the better.
So I have enabled osc PLL x 4
Now with a 10MHz osc, the chip will be running a 10x4 = 40MHz

Hi medelec35,

I have not seen ! used before (Output = !Output), can you explain it's function?

Thanks,
ben

Harry Tuttle wrote: (Output = !Output), can you explain it's function?

Thanks,
ben

Hiya Ben

I have used '=!' as a bitwise 'not equal to'.
So what it does is toggles the value of Output.
So If Output = 0 then after Output = !Output
Output will change to 1

If Output = 1 then after Output = !Output
Output will change to 0
etc.

So in this case was toggling port A0 every time interrupt was accessed.

I find it an easier method to learn than
Toggle = (Toggle XOR 0b11111111) AND 1

The 1 on the far right is the bit you want to toggle.
So if you want to toggle bit 3 you will need to use
Toggle = (Toggle XOR 0b11111111) AND 4
etc.