Frequency counter

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
lock attach
Attachments are accessible only for community members.
Anonymous
Not applicable

I've built a frequency counter on PSOC 4 (CY8CKIT-49-42XX), starting from one example found on Internet.
I'm using UDB block just to learn to use them. (May be simplest?)
The project seem to work , but the frequency shown on LCD isn't precise. The readouts on display oscillate  around 6 -7 % lower, from the correct value (compared with external frequency meter and oscilloscope).
I'm not sure why, may be the clock reference? This clock is precise within 1% (as declared on composer), so I doen't aspect  a so large oscillation.
Where is my mistake? Can the clock reference be the cause my error, or is something on my implementation?
Better if I use an external clock?

   

Attached the project.

   

Thanks for help,
Fabrizio

0 Likes
2 Replies
Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

Youe Clock_2 is running at 12MHz and not at 10 as your calculations show. Furthermore is the precision of your clocks 2%, not 1%.

   

 

   

Bob

0 Likes
Anonymous
Not applicable

Ok, but the clock_2 isn't related with the counting precision. The precision is due by the clock_1.
I've checked the internal clock (Pin_1 and PWM_Out) and they seem to be precise even better than 2%, and LCD readout is more imprecise.
Anyway, I'll try with an external clock.

   

Thanks for your help.

   

Fabrizio

0 Likes