Olimex Support Forum

Others => FPGA => Topic started by: Lee Noack on October 03, 2017, 08:51:24 am

Title: External Clock
Post by: Lee Noack on October 03, 2017, 08:51:24 am
Hi,

Does the ext clk refer to an external clock in or the clock out of the crystal. I wish to feed an external clock in to the board.
Title: Re: External Clock
Post by: LubOlimex on October 03, 2017, 01:26:14 pm
Usually, yes, it is meant for external clock source. It is a good idea to mention which board exactly you have in mind, though.
Title: Re: External Clock
Post by: Lee Noack on October 04, 2017, 02:16:32 am
Ah yes. It is the ice40HX1K-EVB however the other boards have the same or similar clock cct.

Can't insert/attach cct, sorry.

(//)

Title: Re: External Clock
Post by: LubOlimex on October 04, 2017, 02:53:32 pm
In iCE40HX1K-EVB we have already provided external clock. EXTCLK is generated by the 100Mhz oscillator CR1. Refer to this excerpt of the schematic: https://i.imgur.com/XKJaFmO.jpg