Measuring frequency using PSoC 1 | Cypress Semiconductor
Measuring frequency using PSoC 1
Frequency measurements are a common requirement of many applications.
AN2283 - PSoC® 1 Sensing - Measuring Frequency gives a good overview of the many methods that can be used along with their relative error in measurement.
The sample project in the above link, provides an example implementation that is accurate to 0.0016% (16 ppm).