Forum Discussion
Occasional ContributorMAX10 Internal OSC. Only 55 or 116 Mhz? Nothing between?
Your last observation is correct. The internal oscillators on these parts are not capable of high accuracy and have a very wide range that they may operate at. Thus you could see the internal oscillator vary from 55MHz to 116MHz and all you can count on is the frequency you will see on a particular part is somewhere in that range. It will also vary over operating temperature and voltage range. Part to part variance will also occur, of course.
So if you need a precise frequency for operation you MUST use an external reference such as a crystal oscillator based device or a known accurate frequency source.
Occasional ContributorI found this on Youtube. He using a QSYS project to set the frequency it seems. Is this the way to choose frequency?
Frequent ContributorHi Peter
Thanks for your inquiry.
For output frequencies other than default frequencies available for internal oscillator, we can use divider to create them.
There are couple of design examples available here:
https://fpgacloud.intel.com/devstore/platform/?search=oscilla&acds_version=any
Thanks.
Eng Wei
- PYtte
That is a solution when you know the frequency but from what I gather you implement the Internal Oscillator and get a frequency within the range of 55 to 115 MHz. There is no way for me to set a specific frequency. If I have a protocol that require precise timing I have to know the clock speed. I can´t have one board where the FPGA is running at 55 MHz and one where it is running at 116 MHz.
I will just implement a external clock on our PCB so I can make sure I have a specific frequency.
ak6dnRegular Contributor
Your last observation is correct. The internal oscillators on these parts are not capable of high accuracy and have a very wide range that they may operate at. Thus you could see the internal oscillator vary from 55MHz to 116MHz and all you can count on is the frequency you will see on a particular part is somewhere in that range. It will also vary over operating temperature and voltage range. Part to part variance will also occur, of course.
So if you need a precise frequency for operation you MUST use an external reference such as a crystal oscillator based device or a known accurate frequency source.
- EngWei_O_Intel
Hi Peter
There are some variations in the internal oscillator frequency because of the process, voltage, and temperature (PVT) conditions. We need external clock source for high accuracy clock.
Thanks.
Eng Wei
