[arm-allstar] CTCSS detect ping-pong - stumped

[Kevin Custer]

Robert,

Try a 1k pull-down resistor.

The CM1XX chipset requires a ground to become active, and you may not be 
pulling it low enough to be stable and assert the logic change properly.

Kevin W3KKC



On 10/26/2018 10:04 PM, "Robert Conklin via ARM-allstar" wrote:
> Greetings all. I'm stumped on a ping-pong PTT issue when using ctcss detect
> output from my repeater's receiver.
>
> Here's the layout:
> Hamvoip 1.5 code, fresh image w/latest updates.
> DMK URI
> Motorola MTR2000 repeater in base mode. Programmed for PL on input and
> output.
> The MTR's CTCSS and COS detect outputs are active high (5vdc), I use a 10k
> resistor to pull them low when inactive.
> When using CTCSSFROM in usb mode, the CTCSS signal pin-pongs in fairly (not
> perfectly) regular intervals, at about 1Hz, thus the PTT ping-pongs with
> it. If I use COS, no ping pong. Transmission coming from telemetry or from
> links are unaffected so it appears to be a repeater issue.
> I scoped the COR and CTCSS signals and they appear completely identical in
> amplitude, accept the CTCSS signal drops in and out BUT it only does that
> when it's hooked up to the URI. That's the kicker, that CTCSS signal is
> solid as a rock when I take it of the URI. I tried another URI with the
> same result. I cannot see anything in the RSS programming for the MTR that
> would change that CTCSS pin's behavior.
> Would be very appreciative of any thoughts or ideas, thank you!
>
> --
> Robert Conklin
> *N4WGY <http://qrz.com/db/N4WGY>*
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