hamster Posted October 29, 2012 Report Share Posted October 29, 2012 I've just finished my 8 digit frequency counter - I'm just waiting for a GPS module to arrive so I can use it as the reference timesource.Here's a block diagram of the project:And here is a photo of it in action, when using a one pulse per second generated from the local Xtal as the reference.Full source is up on my wiki at http://hamsterworks....equency_counterThis post has been promoted to an article Link to comment Share on other sites More sharing options...
johnj Posted October 29, 2012 Report Share Posted October 29, 2012 The ham radio guy in me thinks this is great! I think you're only a handful of components and some simple math away from an LC meter. Link to comment Share on other sites More sharing options...
hamster Posted October 31, 2012 Author Report Share Posted October 31, 2012 I've updated the project to now work at up to 100MHz by added a DDR Input to the edge detector.Here is a video of it displaying what should be a 96.875 signal - the xtal is about 20ppm fast, when using the Papilio One as a reference. Only the last digit flicks up and down, until I touch the oscillator toward the end. Note the ghetto twisted pair required to get the test signal onto the Papilio One :-). The +- 20Hz dip at the end is when I put my finger on the Nexys2's oscillator! And just to prove my loathing the the Basys2's oscillator is well founded, here is a video comparing the stability of the Nexys2 and Basys2 boards: Link to comment Share on other sites More sharing options...
neslekkim Posted October 31, 2012 Report Share Posted October 31, 2012 You need to get the 16digit version from DX now, so you can increase the counter further? http://dx.com/p/jy-mcu-16x-digital-tube-yellow-led-module-104311?item=2 Link to comment Share on other sites More sharing options...
hamster Posted November 6, 2012 Author Report Share Posted November 6, 2012 And finally the Digilent GPS PMOD has arrived - everything works as expected.Jack, my Papilio One's crystal is about 20 parts per million too slow - what ya gonna do about it? I need my extra 698Hz! Link to comment Share on other sites More sharing options...
Jack Gassett Posted November 6, 2012 Report Share Posted November 6, 2012 Ha! I have a whole roll of them I can send until you find the right one. Jack Link to comment Share on other sites More sharing options...
Peter Aus Wyk Posted January 13, 2013 Report Share Posted January 13, 2013 Hello all, maybe I have a stupid question but I'm unsure how to connect the Display unit from Dealextreme to the papilio. As far as I found this Display likes a Vcc of 5V. This 5V obviously is supplied through the Papilio. The IO of the Xilinx isn't 5V tolerant isn't it? Can someone explain me, why it is possible to connect the papilio and the display anyways please? Should I study the datasheet more in depth? RegardsPeter Link to comment Share on other sites More sharing options...
hamster Posted January 13, 2013 Author Report Share Posted January 13, 2013 Hi Peter The display also works at 3.3V. Mike Link to comment Share on other sites More sharing options...
Peter Aus Wyk Posted January 14, 2013 Report Share Posted January 14, 2013 Thanks Mike for clearing things up I was confused because of Page 4 pin function in the data sheet Vdd is stated to be 5V +/-10% On page 12 electrical characteristics Vdd is called logic supply voltage in the range -0.5 to 7V Now I understand the tables on page 12 a way better. 5V for Vdd is recommended but not a demand. For a logical high 0.7Vdd is the minimum value (2.31V with 3.3Vdd) and low should be beyond 0.99V Again thanks a lot Many regards PeterHi Peter The display also works at 3.3V. Mike Link to comment Share on other sites More sharing options...
neslekkim Posted January 14, 2013 Report Share Posted January 14, 2013 Which datasheet are you referring to? Link to comment Share on other sites More sharing options...
hamster Posted January 14, 2013 Author Report Share Posted January 14, 2013 The datasheet for the LED driver / interface chip on the display board can be found by googling for "filetype:pdf TM1638.pdf" - e.g. http://csserver.evansville.edu/~mr63/Courses/Projects/TM1638en.pdf Link to comment Share on other sites More sharing options...
neslekkim Posted January 14, 2013 Report Share Posted January 14, 2013 Yes, I already have that one, but no voltages discussed on page 4, and no tables on page 12, so I was wondering if someone had found another datasheet, either for the board it self, or the chip Link to comment Share on other sites More sharing options...
Peter Aus Wyk Posted January 14, 2013 Report Share Posted January 14, 2013 Which datasheet are you referring to?ah sorry missed to include the link https://docs.google.com/file/d/0B84N2SrJaybwZTgxYjM4ZmEtY2EyZi00YjVjLWIzOTctYTlhMjJkM2MxMTBl/edit?pli=1 Link to comment Share on other sites More sharing options...
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