David J Taylor wrote:
Is there any other way to watch the signal to see if it's reaching the
serial port correctly?
I would use my 'scope, but even an analogue voltmeter might work - see a
regular flick of the needle. I built the equivalent of a simple
break-out box into my two connections, one in the RS232 DB-9 plug itself:
I checked pps from MSF rx with digital meter and that showed a
signal but not very well. That has a 50ms pulse so 100ms from
Garmin should be as easy to spot. Analogue meters I have around
would give a much better indication.
Another alternative is a transistor + three resistors and
LED. A pot could be used for R2 to confirm voltage swing
of PPS output.
+5V -- R3 --- LED ---+
|
c
pps --- R1 ---+--- b
| e
R2 |
| |
0V ----------+------+
David
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