Digilent ChipKit Max32 Operating Voltage

Created Thu, 18 Jul 2013 21:36:57 +0000 by Jul_Frosch

Jul_Frosch

Thu, 18 Jul 2013 21:36:57 +0000

Hi everybody, I just have a short question about the Max32 Board and it would be really nice, if someone, who has this board, can answer it. What is the operating Voltage (NOT the input voltage) for the Digilent ChipKit Max32 Board? I can't find the answer anywhere :(

Thanks for helping, Jul

majenko

Fri, 19 Jul 2013 07:26:38 +0000

The main chip (the pic32mx795f512h) operates between 2.3V and 3.6V.

The board has a 3.3V low-dropout regulator running from a 5V regulator, which is fed from the main input.

The "operating voltage" of the board could be said to be 3.3v as that is the voltage the main chip runs at.

Jul_Frosch

Mon, 22 Jul 2013 11:54:10 +0000

Thanks! That was really helpful. But I can't use it, because I'm searching for an 32bit Microcontroller, which is Arduino compatible and runs on 5V

majenko

Mon, 22 Jul 2013 12:05:00 +0000

That's going to be a tough call.

Why does it need to be 5V?

Jul_Frosch

Tue, 23 Jul 2013 06:35:17 +0000

I thaught rhis question would come up.

Because I have an Project with a Cellular shield and a Display, and they are both working at 5V. I tried to find a Display at 3.3V and that was no problem, but I dind't a Cellular Shield working at 3.3V. So it has to be 5V. Are there any 32bit microcontrollers working at 5V?

Thanks for your help

majenko

Tue, 23 Jul 2013 09:13:48 +0000

That's no reason to require a 5V microcontroller. yes, a 5V one makes things simpler, but only slightly.

1. 3.3V is within the V[sub]IH[/sub] range of most devices, so a 3.3V microcontroller can usually drive a 5V device fine.
2. Some pins on the board are 5V tolerant, either through protection on the board or the pins themselves being tolerant, so you can interface a 5V device direct to those pins.
3. Level shifting for those situations where 1 and/or 2 won't work is simple enough, with many ways of implementing it - from dedicated high speed level shifting chips to just a couple of discrete components for simpler slow speed applications.

It's just the same as running a 3.3V shield on a 5V microcontroller - just the opposite way around.

There certainly aren't any 5V 32-bit micrcontrollers from Microchip. A handful (13) of the Atmel 32-bit AVR range of microcontrollers come in a 4.5-5.5v version (that's not the chip that's on the Due, so that's out), and they are all SMD chips with between 64 and 144 pins (TQFP).

jmlynesjr

Tue, 23 Jul 2013 17:56:05 +0000

I had no problem driving the 5v versions of the Sparkfun 2-line LCD display and the 4-digit LED display with 3.3v.

As Majenko said, 3.3v is above the Vh of 5v chips. What the heck, give it a go.

James

caroper

Tue, 23 Jul 2013 23:04:17 +0000

I drive a Telit 3G Module with a PIC32MX 3V3 device also no issue, but the telit module is not a shield, same principal applies though.

Cheers Chris

Jul_Frosch

Wed, 24 Jul 2013 23:18:22 +0000

Thanks for all that fast help!! And I think I got your point :P :P :P

Jul

mikes

Thu, 25 Jul 2013 13:21:29 +0000

If your output absolutely has to be 5 volts you could set the digital outputs to open drain and use a pull up resistor.

http://www.chipkit.org/forum/viewtopic.php?f=17&t=2224&p=8380#p8380

PS Make sure the pin is 5 volt tolerant and has open drain capability to avoid damaging your processor.