Question: How can you connect an external clock to PSoC®? The PSoC’s-dedicated MHz oscillator pins appear to be used only for an external crystal. The oscillator of interest is in the 10–20 MHz range, can drive a CMOS load of 15 pF, and has a rise/fall time of 6 ns.
To use an external clock source, please follow these steps:
- Place a digital input pin in your top design.
- Draw a wire from that pin and give a name to that net.
- In the .cydwr window, go to Clocks tab and double-click Master Clock.
- A window named Configure System Clocks will open. In this, check the Digital Signal and click on the Browse button.
- Then select the net that you gave for the pin (clock input) previously and give the frequency and tolerance value.
- Now you can use this clock to derive any clock source.
For further information, please refer to the application note PSoC 3 and PSoC 5LP Clocking Resources.