Hi all,
I have more or less accidentally connected a RS232 Signal directly to a uC (some kind of ARM i believe) with no MAX232 in between. Did I definitely kill the controller? I haven't tried with TTL converter yet because I'm still waiting for delivery.
Is there a way the uC has survived?
Cheers
Probably damaged the IO pins at least. 3.3V and 5V parts don't like having +/-10V (or more) applied to them.
MAX232? Do they still sell those things anymore, LOL?
You may be in luck because, even though the voltage levels are around +/-10V, the
MAX232 charge-pumps are severely current-limited to a providing a few mA, so a load
such as an Arduino I/O pin, ala clamping diode, may have dragged the MAX232 output
voltages down below lethal levels. Maybe.
See first figure, page 4,
http://datasheets.maximintegrated.com/en/ds/MAX220-MAX249.pdf
No info given as to what was driving the lines he connected up tho - could have been much higher voltage and from a higher drive current capable part.
I got that, just figured that he mentioned MAX232, so I went there, ha.
oric_dan:
I got that, just figured that he mentioned MAX232, so I went there, ha.
No, he mentioned a lack of MAX232...
We need to know what arduino it was and what it was being driven from.
Some combinations are more robust than others.
However if you can still down load sketches the chances of getting away with it are good.
Grumpy_Mike:
We need to know what arduino it was and what it was being driven from.
Some combinations are more robust than others.
He didn't say is was an Arduino but "some sort of ARM". Those things are delicate, nowhere near as robust as AVR chips.
He didn't say is was an Arduino but "some sort of ARM".
Yes I spotted that but is was a very vague wishie washie sort of thing to say. If you have a Due and you don't know it is a Due then you don't deserve to have one.
fungus:
oric_dan:
I got that, just figured that he mentioned MAX232, so I went there, ha.No, he mentioned a lack of MAX232...
As Murphy said, when info is minimal, then 2nd guessing is maximal. I conjectured
he may have had a MAX232 on the "other" end.
i've connected direct output from USB-RS232 Adapter to this one here http://www.atmel.com/products/microcontrollers/arm/sam7x_xc.aspx
Now i've tried to abuse my uno as a level shifter, which i haven't thought of before, and still no signal..which probably means that the serial pins are dead 
Zuluriney:
i've connected direct output from USB-RS232 Adapter to this one here http://www.atmel.com/products/microcontrollers/arm/sam7x_xc.aspxNow i've tried to abuse my uno as a level shifter, which i haven't thought of before, and still no signal..which probably means that the serial pins are dead
So, in the words of Tommy (Brad Pitt) from the movie Snatch, "Proper Screwed"
