hello all I was wondering where can I get a 48MHz oscillator, the available one are 50 and 45. the FPGA board I am using has a dividable 100MHz, so I can get 50 or 33.3 or 25 .... MHz. the USB1.1 core needs a 48MHz. I brought a 48 MHz crystal, but the circuit with 74F04 inverters is not working on well, it seems the frequiency is so high. should I try CMOS inverters or is there any better solution. I know there is a DLL (or PLL) inside the Spartan II FPGA, can I get a 48 M out of it? one more thing what is the function of the following ports in the USB1.1 core: Vendor_data ep_sel wIndex wVAlue v_set_feature: v_set_int thanks in advance M. Abukhater --------------------------------- Do you Yahoo!? Win a $20,000 Career Makeover at Yahoo! HotJobs -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040502/2c51b49d/attachment.htm

Have a look at Digikey (http://www.digikey.com/) or Mouser (http://www.mouser.com) You can get a 48MHz oscillator for about $2. Meng WMS Designs

Hi, i used a DCM (Digital clock manager) of a virtex II to double a clock frequency, but it can also div and mult frequency's. Check your spartan II data sheet or user guide, if you have a DLL or DCM you should be able to fiddle around with clocks to get your 48 MHz. Regards, Egwin Wesselink. ----- Original Message ----- From: M. AbuKhaterperocletos@y...> To: Date: Sun May 2 11:58:53 CEST 2004 Subject: [usb] Oscillator

Hi Actually I do have a DLL on the spartan, but the board comes with 100MHz oscillator, can I get a 48M out of this one. besides it seems I dont have the DCM, how can I get it, I have the ISE from Xilinx, can I access the DLL from this software? Regards Abukhater wesselin@natlab.research.philips.com wrote: Hi, i used a DCM (Digital clock manager) of a virtex II to double a clock frequency, but it can also div and mult frequency's. Check your spartan II data sheet or user guide, if you have a DLL or DCM you should be able to fiddle around with clocks to get your 48 MHz. Regards, Egwin Wesselink. ----- Original Message ----- From: M. AbuKhater To: Date: Sun May 2 11:58:53 CEST 2004 Subject: [usb] Oscillator _______________________________________________ http://www.opencores.org/mailman/listinfo/usb --------------------------------- Do you Yahoo!? Win a $20,000 Career Makeover at Yahoo! HotJobs -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums/usb/attachments/20040504/5420ee55/attachment.htm

Hi, first of all you should have a source library with your fpga, mine was something like virtex2.v or virtex2.vhdl. The DCM or your DLL should be defined there as a black box for synthesis. You can either infer the DLL with synthesis directives or instanciate the DCM (make a DCM instance in your RTL code). Either way you need to add some synthesis directives in your constraints file. Check the xilinx website there's plenty of documentation. i dont know whether the DLL will give you the 48 MHz, because it's basically a primitive of the DCM so i don't know whether it has the same options/features. Check it out yourself on the xilinx website. Regards, Egwin Wesselink. ----- Original Message ----- From: M. AbuKhaterperocletos@y...> To: Date: Tue May 4 15:33:41 CEST 2004 Subject: [usb] Oscillator