[GPS_Standard] Simplified GPS Freq Std. Problems

[Bert, VE2ZAZ]

Hi Jim,

Serial port issues are the most common issue reported. They are
    always rapidly resolved. At least, you know that the
    system is alive. Do you have access to an oscilloscope? Probe all signals in
    the TX chain and then in the RX chain. Make sure to observe the TTL TX and RX pulse shapes carefully. Do you have another converter board you could swap? Be suspicious about that FTDI232 board. 

Did you check the supply carefully on the PIC's pins 20 and 8? These 
chips can be back-driven from other I/O pins and may run without Vdd 
applied, though they will behave erratically... 

Note that the PIC will not echo back on the characters you type. You must turn on echo in Putty if you want to see what you are typing. 

There is no point trying to use the Montrol S/W until your link is solid. But when you will have fixed the issue, once in Montrol, make sure to press <Return> after typing in a parameter value, otherwise the new parameter will not take.

This is a simple problem that should be easy to fix. Several hundred of these systems are running, so that should give you confidence...

Best.

Bert, VE2ZAZ

> Date: Sun, 27 Sep 2015 14:17:57 -0400
> From: jburney at unifiedinstruments.com
> To: gps_standard at mailman.qth.net
> Subject: [GPS_Standard] Simplified GPS Freq Std. Problems
> 
> Hi Bertrand Zauhar,
> 
> 
> I am having a few problems with implementing your design, and was hoping you
> could answer a few questions.
> First, this is been built on a breadboard, PIC was programed with a data i/o
> unisite, lastest software was used.
> 
> My main problem is sending commands to the PIC, first there does not seem to be
> any echo back of a command sent,
> and the second, the PIC seems to be very unresponsive to a command sent to it.
> If I send it the command ? 'enter' I may or may not get the command list, most
> of the time, I don't get a response back.
> Should note that I am using Putty on a windows PC and a FTDI232 chip to talk to
> the PIC here, data send looks good.
> 4800 baud, 8,n,1.
> 
> When using the monitoring tool, I am also unable to set any of the parameters
> with it as well.
> 
> Below is a sample output from the pic;
> 
> U|U|03FB0|.|.|236C|0001|FFFF|0001|00
> U|U|03FB0|.|.|50C2|0002|FFFE|0002|00
> U|U|03FB0|.|.|655D|0003|FFFD|0003|00
> U|U|03FB0|.|.|66AC|0004|FFFC|0004|00
> U|U|03FB0|.|.|687D|0005|FFFD|0005|00
> U|U|03FB0|.|.|68B0|0006|FFFE|0006|00
> U|U|03FB0|.|.|6B6A|0007|FFFF|0007|00
> U|U|03FB0|.|.|6A4B|0008|0000|0008|00
> U|U|03FB0|.|.|CDBB|0009|0001|0009|00
> U|U|03FB0|.|.|FEE3|000A|0000|000A|00
> U|U|03FB0|.|.|6624|000B|FFFF|000B|00
> 
> Any ideas from you as to what I maybe doing wrong here would be of great help.
> 
> Thank you so much for your time, Jim Burney
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