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evnow
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Re: Part Sources for CAN Projects

Wed Jul 13, 2011 9:19 pm

BTW, you think 5V works ok ? The doc says 7 to 12 Volts.

If 5V works ok, we can just convert a USB cable to supply power.
Power should be applied to CON2PV2-2.5MM connector. AVR-CAN could be
powered by applying up to 12VDC (7 to 12 VDC) to EXT1-1 and EXT1-2 and GND
to EXT1-3 and EXT1-4 or if you supply 7 to 12 VDC to CON2PV2-2.5MM pin 2
(VIN) and GND to CON2PV2-2.5MM pin 1 .
1st Leaf : 2/28/2011 to 5/6/2013
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garygid
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Re: Part Sources for CAN Projects

Thu Jul 14, 2011 6:54 am

Evnow,
You are right, 5v should not be used to power the AVR-CAN board. I fixed my post, THANKs.

The on-board regulator that produces the 5v for the board will NOT work if supplied only 5v on its input. It needs about 1.5 volt (or so) more than 5v, so they specify the 7v minimum.

It works at 12v, but the regulator chip gets hot, especially if the board's 5v is ALSO being used to power something else, like a Display and/or an RS232-driven JTAG programmer.

I was told that the regulator chip's input voltage rating is over 15v, but I have not verified this myself. Power dissipation is the larger issue (the regulator getting too hot). So, the LEAF's 12-to-14v supply does seem to work OK, at least for shorter periods of time. But, 7v to 9v is safer, so I now use the 5v zener diode to cut the 12-to14v down to 7-to-9v.

So, the 7v to 9v range is best, I use the $4 switcher 8.4v DC power supply from All Electronics.
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lincomatic
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Re: Part Sources for CAN Projects

Thu Jul 14, 2011 8:49 am

evnow wrote:BTW, you think 5V works ok ? The doc says 7 to 12 Volts.

If 5V works ok, we can just convert a USB cable to supply power.
Power should be applied to CON2PV2-2.5MM connector. AVR-CAN could be
powered by applying up to 12VDC (7 to 12 VDC) to EXT1-1 and EXT1-2 and GND
to EXT1-3 and EXT1-4 or if you supply 7 to 12 VDC to CON2PV2-2.5MM pin 2
(VIN) and GND to CON2PV2-2.5MM pin 1 .
As Gary said, you can't use 5V as input to the voltage regulator. However, if there's a 5V pin somewhere on the board, you can apply 5V from USB to the circuit there, bypassing the regulator. This is how the Arduino runs off 5V USB. When you power it from USB, it bypasses the regulator.

GroundLoop
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Re: Part Sources for CAN Projects

Thu Jul 14, 2011 10:35 am

The AVR-CAN could be powered by a 9v battery, but one must be careful to NOT lose power in the middle of flashing, or the micro-processor could become un-responsive (effectively dead). I do not have enough experience with the Atmel AT90CAN123 uP to evaluate the risk, but it usually exists.
I don't think so.
The ISP or JTAG can always recover the board from incorrect or partially flashed programming, including the bootloaders.

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evnow
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Re: Part Sources for CAN Projects

Thu Jul 14, 2011 12:26 pm

GroundLoop wrote:
The AVR-CAN could be powered by a 9v battery, but one must be careful to NOT lose power in the middle of flashing, or the micro-processor could become un-responsive (effectively dead). I do not have enough experience with the Atmel AT90CAN123 uP to evaluate the risk, but it usually exists.
I don't think so.
The ISP or JTAG can always recover the board from incorrect or partially flashed programming, including the bootloaders.
Not sure who wrote that original quote - I'd say, using 9V battery is probably the safest best if you want to make sure you would have power during flashing. Just check voltage before flashing to make sure the battery is not about to die (which anyway it won't since the battery dies slowly).
1st Leaf : 2/28/2011 to 5/6/2013
2nd Leaf : 5/4/2013 to 3/21/2017
Volt : 3/25/2017 to 5/25/2018
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