Joe,
     Would you please? Here is my email address:
mechanic_2@charter.net
Thanks,
rich!

On 6/23/2014 3:30 AM, IVP wrote:
> The topic deserves to be in [EE]
>
>> I also thought about using a PIC to supply the time base, the
>> reset pulse, the gating window, and the latching signal, but I
>> don't even know where to begin but I am sure that it could be
>> done pretty easily with the PIC
> I've got a project for a 2.5GHz 12-digit Frequency Counter
> that is "fairly" simple, although it has some quite intricate
> interconnections. It's mostly logic but has a 16F877 supervising
> and driving the LEDs, although that is done indirectly.
>
> http://www.siliconchip.com.au/Issue/2012/December
>
> The timebase is a cystal-controlled (32kHz) 4060 and gating is
> via 4518 decade dividers, 1s to 1000s. Enabling of the counters
> is by way of 74AC74 flipflops, flipped by the selected gate
> frequency of 1Hz, 0.1Hz, 0.01Hz or 0.001Hz
>
> Counting is done with a 74AC163, 74HC160 and 4518 for the
> first (most significant) 4 decades and the PIC counts the least
> significant 8 decades with TMR1. The first 4 decades are presented
> to the PIC through a pair of common-buss 74HC244 and read
> on completion of the gate period, before s/w resets the counters
>
> The PIC outputs that will be of interest to you are Reset Decades
> 1 & 2, Reset Decades 3 & 4, Read Decades 1 &2, Read Decades
> 3 & 4, Set Main Gate Control FlipFlop, Sense Main Gate Status,
> and Enable Control Signal Latch and Sense Switches (a row of 8
> pushbuttons which select the gating time and channel etc. which
> are latched into a 74HC373 by the PIC)
>
> Some of what the PIC does indeed mean fewer logic chips, but
> it's not an indispensable useage
>
> As above, a flipflop enables the counter chips. A one-shot reset,
> as can be made with a couple of 4001 gates, will zero the counters
> when triggered by the flipflop transition. Another one-shot can
> latch the data after a time delay less than 0.1s (your fastest sampling
> speed). This delay, for example 0.09s, can be yet another one-shot.
> The latch is then released to store the new counting.
>
> Do you get what I mean ? Everything is enacted by the transition
> of the gate signal. Resets can be done very simply and quickly and
> shouldn't impact greatly on accuracy, ie the odd missed incoming.
>
> If you want more details and/or the schematic, let me know
>
> Joe

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