Quote:
Originally Posted by kamocat
This is a good point, but it doesn't seem to add up.
Most of the inputs have a resistor (1k or greater) inline with their power supplies. There are two exceptions to this: the encoder and the brake/coast jumper.
Furthermore, limit switches are active when they are left OPEN. Their default state is closed (when the jumper is installed). This means a limit switch must be "normally closed", and break the connection when pressed. When a limit is pressed, it is drawing LESS power than when it is.
It was a good suggestion, though. I'm curios how close the Jaguar is to drawing more than their power supplies can handle.
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I'm not entirely thinking in terms of DC voltages and currents.
I'm thinking of it more like an antenna...merely a piece of wire.
In some cases they have it plugged directly into the microcontroller.
Take for example the limit switches...no AC decoupling capacitors.
Even the potentiometer input...no AC decoupling.
Even the grounds could be an issue if you extend the ground plane out the wrong way.
In the black Jaguar the 5V power supply is a: TPS54040
"3.5V to 42V Input, 0.5 A Step Down SWIFT™ Converter with Eco-Mode™ "
http://focus.ti.com/lit/ds/symlink/tps54040.pdf
The 3.3V regulator is:TPS73633
"Single Output LDO, 400-mA, Fixed (3.3 V), Cap-Free, Low-Noise, Reverse Current Protection"
http://focus.ti.com/docs/prod/folder.../tps73633.html
The microcontroller the: LM3S2616
http://www.luminarymicro.com/product...html#Datasheet