Serial-tap: Mix RS485 control signals (eg CTS) with TTL data signals

I am using TTL serial communications. I have some "trigger" events I'd like to log in capture buffer along with the data. These are not TTL compatible , but should be fine for a RS422/RS423 receiver chip.

I would like to trigger IO-Ninja on these events so as to help run down things that happen just before the trigger.

Thanks.

Let's make sure I understand correctly. You capture an RS485 data flow using a Serial Tap but also want to add extra records into the log to mark certain external events. Right?

One solution would be to connect any of the DTR/DSR/RTS/CTS lines of your Serial Tap to the box that would wiggle this line to mark such an event. Any changes of control/status lines are visible in the log and thus can be used to approximately find the times of your external events (thus reducing the amount of logged data for you to analyze).

I was actually hoping to connect a TTL data flow, but have data signals I'l like to add the the data log to help with data analyzsis.

I was wondering if "RS-485" control signals can be logged along TTL data signals. This is because I know what RS-232/422/423/485 signal specifications are & can be sure my signals are in range (eg +/- 30V)

There are no "specifications" given for signal voltage, etc, for the TTL inputs. I would like to be able to directly connect from my logic analyzer to the serial-tap, but without specifications on the input levels, etc I can't be sure I won't blow up the serial tap.

One related note: what are the minimum pluse durations so that the control signal changes are recorded in the log?

I was trying to find a solution that lets me have a nice data logger, with serial decode w/o having to fabricate an interface board to everyone happy.

Oh, it looks like I misunderstood. So, you actually are capturing a TTL data link and want to be able to add external signals to the log.

First, you can't pass both RS485 and TTL signals to the tap simultaneously; the RS232/RS485/TTL mode switch in the middle physically disconnects all lines except the selected interface.

However, you can utilize some unused DTR/DSR/CTS/DSR lines of the TTL section in the terminal block; voltage levels can be found in the specification:

Supported TTL logic levels: From 3.3V to 5V

As for the minimum pulse duration on the control lines -- the chip that we use guarantees reliable capture of serial traffic up to 1Mbps. But that's for the data lines; we couldn't find such guarantees for the control lines. Most likely, it's of the same order of magnitude. Another idea to reliably mark points in the log is to toggle the state of a control line instead of pulsing it.

Question: Does Io-Ninja support other sniffers / RS485/USB converders than the Tibbo HW. The converter I use is a small build-in device, unable to exchange due to it's small size. IF it does not support other devices, I need to find other SW .....

@bartho-dröge

IO Ninja can work with any USB-to-Serial adapter via the Serial Terminal plugin.

As for other hardware Serial sniffers, we have plugins for EZ-Tap Pro/VersaTap and for any generic dual-COM tap.

You can run a free evaluation to try and see if everything works for you before purchasing; let me know if your evaluation is over and you need to extend it.

@vladimir said in Serial-tap: Mix RS485 control signals (eg CTS) with TTL data signals:

try and see if everything works for you before purchasing; let me kno

Interestingly I can only download if I purchase ($35). I have a paid license for IONinja,

@bartho-dröge

Uhm, not quite sure what you mean? It's actually OK to download IO Ninja packages even without signing in to ioninja.com

Serial Terminal requires the capability org.jancy.io.serial, yes. But still, it doesn't stop users from downloading and running evaluation.

But wait, in your case, you have an active subscription, so everything should be unlocked and available. Please let me know if it's not the case and you have problems accessing some functionality...