[GPS_Standard] VE2ZAZ

[Roberto Barrios]

Hi Bert,

You are right, Schmitt Trigger inputs have a 4V minimum voltage requirement
for Vih. I did not think about the buffer type when checking their
compatibility...

It is somehow working fine for me, but the proper way to do it would require
a level converter. Since GPS a controller share a common ground, I think a
transistor plus two resistors for the high state would work.

Thank you,
Roberto EB4EQA

-----Original Message-----
From: Bert, VE2ZAZ [mailto:ve2zaz at sympatico.ca] 
Sent: martes, 08 de junio de 2010 13:46
To: Roberto Barrios
Subject: VE2ZAZ

Hi Roberto,

I go by memory here, but I think the minimum-high spec on the TTL input of
the PIC is 4V. It may work in your case, but I know it did not for some
other users. You are probably very borderline and your performance may
degrade over time/temperature.

73,

Bert, VE2ZAZ
http://ve2zaz.net

Roberto Barrios wrote:
> Hi Bob, Bert,
> 
>  
> 
> I've got one Resolution-T running on my VE2ZAZ standard. The datsheet says
somewhere it's (3.3V limited) output is TTL compatible. Yes, some interfaces
are pickier than others, but my PCB from Bert is working fine without
further modifications.
> 
>  
> 
> I agree with Bob, this is a fine GPS timing receiver. Better specs,
smaller, less power-hungry and with much more functionality than the older
Motorola Oncores. The software for this receiver (DSPMON) from Trimble is
great, but look for version 1.53, not earlier.
> 
>  
> 
> Regards,
> 
> Roberto Eb4EQA
> 
> 
>> Message: 1
>> Date: Sun, 6 Jun 2010 20:09:33 +0200
>> From: "Stig Kristiansen - OZ3XO." <oz3xo at e-box.dk>
>> Subject: [GPS_Standard] preferred GPS
>> To: <gps_standard at mailman.qth.net>
>> Message-ID: <33FE5497EB6C4EC7A70EF8E1010971B0 at 3XO>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> Hi Bob.
>>
>> This 12-Ch GPS is very stabile.
>> http://www.trimble.com/timing/resolution-t.aspx?dtID=overview
>> Extremely accurate 1-PPS output, synchronized to GPS or UTC within 15 
>> ns (one sigma)
>>
>> Stig - OZ3XO.
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Mon, 07 Jun 2010 07:59:36 -0400
>> From: "Bert, VE2ZAZ" <ve2zaz at sympatico.ca>
>> Subject: [GPS_Standard] VE2ZAZ
>> To: "Stig Kristiansen - OZ3XO." <oz3xo at e-box.dk>
>> Cc: gps_standard at mailman.qth.net
>> Message-ID: <BLU0-SMTP70AF489FAF7B6E6C25E153F1D50 at phx.gbl>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> Stig,
>>
>> Great GPS, but be careful as it is a 3.3V unit. The 1 PPS is not 5V 
>> TTL compliant. It will not directly drive the PPS inputs of many 
>> controller boards such as mine. You will need to scale up the 1 PPS 
>> using a complementary pair of transistors, for example.
>>
>> 73,
>>
>> Bert, VE2ZAZ
>> http://ve2zaz.net
>>
>> Stig Kristiansen - OZ3XO. wrote:
>>> Hi Bob.
>>>
>>> This 12-Ch GPS is very stabile.
>>> http://www.trimble.com/timing/resolution-t.aspx?dtID=overview
>>> Extremely accurate 1-PPS output, synchronized to GPS or UTC within 
>>> 15 ns (one sigma)
>>>
>>> Stig - OZ3XO.
>>>
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>>
>>
>> ------------------------------
>>
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>>
>> End of GPS_Standard Digest, Vol 35, Issue 3
>> *******************************************
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