Download waveforms.

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picnut

New Member
I am trying to workout what waveforms exist on a download cable. Normally high or low ?. Also when the edotor does a check to see if the hardware is connected, what does it look for ?. Thanks ...

picnut
 
hippy

hippy

Ex-Staff (retired)
Normally low, 0V ( or negative ) on the physical cable from PC to Serial In pin.

The download protocol is Revolution Education Limited's proprietary Intellectual Property which we do not release to the public.
 
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BeanieBots

Moderator
It's RS232 data comms. +/- 10v if using USB010 and 5v/0v if using AXE027.
The nature of the data is the intellectual property of Revolution Education and is not for general release.

Why do you want to know?

EDIT: Post crossed with Hippy
 
hippy

hippy

Ex-Staff (retired)
Re : +/-10V

Good point, and +/-5V, +/-12V, +/-15V, maximum of +/-25V as per RS232C specification. I've updated the earlier post, but just to make it clear ...

When the PC is idling ( not sending ) the line will be 0V or negative.
 
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picnut

New Member
"Why do you want to know?"

I am creating a project for children between the ages of 8 - 16 and they are smarter than the average adult would want to admit. An eight year old may ask about data transfer, but has no working knowledge of electronics. It occurred to me than if I included data in and data out LED indicators on the boards, it might ward off a lot of questions, because they would then be able to see the pulses going in and out of the boards.
 
hippy

hippy

Ex-Staff (retired)
LED+R's between RX and TX to 0V are a good idea for download in and out. The TX can connect directly to Serial Out leg, the RX should parallel the 10K before the 22K to the PICAXE. Cathode ( pointy-end ) to 0V, off when nothing's happening, on when data is present.

I find it's useful just to see that data is going into a PICAXE on download with the RX LED and have the TX LED flash when using SERTXD / DEBUG - You know you did download into the right board, and you still know it's working even when the Terminal is disconnected.

Because the RX may be +12V while TX will only be +5V you may need a larger R for RX to get the same brightness. Though I can't really tell the difference with high-efficiency LED's and 1K8 for each.
 
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vttom

Senior Member
picnut said:
"Why do you want to know?"

I am creating a project for children between the ages of 8 - 16 and they are smarter than the average adult would want to admit. An eight year old may ask about data transfer, but has no working knowledge of electronics. It occurred to me than if I included data in and data out LED indicators on the boards, it might ward off a lot of questions, because they would then be able to see the pulses going in and out of the boards.
Click to expand...
FYI - The "pulses" come so fast, the LEDs will look more like they're flickering rather than pulsing.
 
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