Can't tell from what you've said how you've killed it. Do you have a schematic of what you built? And what was the voltage of the battery you hooked up? The supply voltage minimum for the L6234 is 7V which is more than the ATmega will tollerate so if that was unregulated that's what I'm thinking you did to smoke the uC.
So long as you only connected ground and signal pins (enables and inputs) to the Arduino there is no way to
affect the Arduino (though you might cook the L6234 if the enables were 5V while the L6234 was not powered up).
With a circuit like this I would first add protection resistors in series with all the signals (4k7 on enables, inputs) so
that if the motor controller blows it won't take out the Arduino. Since the only other common connection is ground
I can't see how you damaged things - before allowing any significant current to flow with a motor you should test with
a current-limited power supply to make sure all is well - its startlingly easy to blow motor controllers if you are
careless. You would at the very least need to check the bootstrap voltage was up to spec and that the outputs were
all switching cleanly with a 'scope to be confident of the thing working under real load.
Also its wise to have quite a bit of decoupling on the Vs rail since the bridge is switching lots of current.
You also haven't said what kind of motor you are using / going to use - this chip will handle perhaps 1.5A or so
with moderate heatsinking, trying to take it to the nominal 2.8A / 4A (package dependent) isn't feasible without water-cooling!
The way i connected it is below.
Im thinking because i connected 5 volts from arduino and used arduino ground i potentially shorted the 5volt to ground?
The motor runs at around 1 AMP
MarkT:
So long as you only connected ground and signal pins (enables and inputs) to the Arduino there is no way to
affect the Arduino (though you might cook the L6234 if the enables were 5V while the L6234 was not powered up).
With a circuit like this I would first add protection resistors in series with all the signals (4k7 on enables, inputs) so
that if the motor controller blows it won't take out the Arduino. Since the only other common connection is ground
I can't see how you damaged things - before allowing any significant current to flow with a motor you should test with
a current-limited power supply to make sure all is well - its startlingly easy to blow motor controllers if you are
careless. You would at the very least need to check the bootstrap voltage was up to spec and that the outputs were
all switching cleanly with a 'scope to be confident of the thing working under real load.
Also its wise to have quite a bit of decoupling on the Vs rail since the bridge is switching lots of current.
You also haven't said what kind of motor you are using / going to use - this chip will handle perhaps 1.5A or so
with moderate heatsinking, trying to take it to the nominal 2.8A / 4A (package dependent) isn't feasible without water-cooling!
MarkT:
So long as you only connected ground and signal pins (enables and inputs) to the Arduino there is no way to
affect the Arduino (though you might cook the L6234 if the enables were 5V while the L6234 was not powered up).
With a circuit like this I would first add protection resistors in series with all the signals (4k7 on enables, inputs) so
that if the motor controller blows it won't take out the Arduino. Since the only other common connection is ground
I can't see how you damaged things - before allowing any significant current to flow with a motor you should test with
a current-limited power supply to make sure all is well - its startlingly easy to blow motor controllers if you are
careless. You would at the very least need to check the bootstrap voltage was up to spec and that the outputs were
all switching cleanly with a 'scope to be confident of the thing working under real load.
Also its wise to have quite a bit of decoupling on the Vs rail since the bridge is switching lots of current.
You also haven't said what kind of motor you are using / going to use - this chip will handle perhaps 1.5A or so
with moderate heatsinking, trying to take it to the nominal 2.8A / 4A (package dependent) isn't feasible without water-cooling!
Hey Matt,
Could you please explain why the chip might get fried if 5 volts is applied from the arduino before the chip is powered? I am trying to have a separate power switch for the drivers
This effect is likely due to something not shown on the schematic for the part you are using, the ESD protection diodes.
If the voltage on a logic pin is above it's supply voltage a diode conducts to the supply pin to prevent damage, this effectively drives a chip from one of it's input. When trying to drive the motor it will pull too much current from the input pin.
MarkT suggested the required protection feature, it's worth re-reading the first two replies.
MarkT:
With a circuit like this I would first add protection resistors in series with all the signals (4k7 on enables, inputs)