This page documents common problems and their solutions.

Hardware problems

The LED is throbbing and my program is stopped!

The LED throbs when there has been a failed software ASSERT() or some other error.

In the case of a failed assertion, a first debugging step you can take is to find out the file and line where the failed assertion took place (for instructions on this, see the ASSERT() documentation linked to above). This may give you some clue about the source of the error.

libmaple often uses ASSERT() to halt immediately when it detects that something has gone wrong, so if you’re not using assertions, then what’s probably happening is that some bug is causing the failed ASSERT() lower down.

If it’s not a failed assertion, then you’re likely looking at something like a hard fault.

There are a few issues with the bootloader which mean you might not be able to upload your program when this happens. You can still reprogram by using perpetual bootloader mode.

My board is bricked! I can’t upload via the bootloader no matter what!

Don’t panic. First, make sure that the board is plugged in correctly for program upload, using the instructions given in the quickstart. If that doesn’t work, try using perpetual bootloader mode.

If that doesn’t work, then you’ve got a problem. All is not lost, however! You can always try to re-flash the bootloader over serial (or JTAG).

If your board really is bricked, and you think it’s our fault, contact us!

My 5v peripheral doesn’t work! (I2C, SPI, USART, etc)

Yup, the Maple is a 3.3v board. You may need to use a level converter. See the Arduino Compatibility, GPIO, or other hardware specific documentation for more information.

The reset and D38/serial buttons don’t seem to work reliably!

A few Maple Rev3 boards shipped in May-June 2010 may have had unreliable buttons; see the Maple Errata for details. We’re happy to replace these for you!

Installation problems

I don’t have root/administrator access!

There are probably hacks or work-arounds to getting programs uploaded without higher level system permissions. If you can access USB character devices (ACM or ttyUSB style), you should be able to communicate with the Maple and reprogram using an FTDI converter and the serial bootloader, but we haven’t tried.

[Linux] I don’t use udev!

There is probably a simple way to get autoconfiguration working with devfs; in the meantime, you could try running the entire IDE as root.

IDE problems

[Mac OS X] The “Board” and “Serial Port” menu items are missing!

Sometimes this happens if you try to compile or upload without having a board selected. The work-around is to restart the IDE. Mysterious!

Common compiler problems


A classic! Make sure you have selected a board from the pulldown menu.

undefined reference to setup()/loop()

Your sketch/program either does not include one of the setup() or loop() functions, or it was not found by the compiler. Your program must include both void setup() and void loop() functions; they don’t have to do anything, but they must be there.

You can start with an example program (to see one in the IDE, click on File > Examples > Stubs > BareMinimum) to get the basic structure. See also the language documentation.

This is a common error when your entire sketch is blank.

error: 'Serial' was not declared in this scope

The classic Arduino has only one USART device and uses the unique name “Serial” to control it. Larger devices like the Arduino Mega and the Maple have multiple USARTS referred to as Serial1, Serial2, etc. You probably want Serial2 on the Maple; that’s the one connected to pins D0 and D1. See also the USART docs.

File(s) not found

There is an intermittent bug with the temporary directory build system that on occasion will lose many of the #included libmaple files. If you recompile everything, it should be fine.

Common upload problems

My program is too large!

First, make sure you’re using the Flash target instead of RAM; there is several times more Flash memory available for user programs.

No DFU capable USB device found

This probably means the Maple isn’t plugged in or powered on. Try unplugging and plugging back in, or pressing the RESET button.

This can also happen if you disable the USB peripheral, e.g. using SerialUSB.end().

I have multiple boards plugged in; how do I know which one will get programmed?

Because the Maple IDE uses DFU to upload programs, you can’t select a particular board to upload to. There’s no solution to this problem for now: you’ll have to just plug in your boards one at a time. If this is a real problem, let us know, and we’ll see if we can come up with a better solution.

My Flash programs don’t seem to stick; they behave like they are RAM!

If you have uploaded a program to RAM, this will take priority over any program subsequently uploaded to flash. We’ll be removing this bug in a later version of the bootloader. For now, you can fix this by unplugging your Maple to clear the contents of RAM, then plugging it back in.

If you are using the Unix toolchain, Make sure you make clean when switching between Flash and RAM targets; our Makefile isn’t smart enough to rebuild everything for the new target.

My code uploads, but it doesn’t work!

Are you sure you have the right board selected? (Maple vs. Maple Mini, etc.)

Command-Line Issues

[Linux] cdc_acm 3-1:1.0: no more free acm devices

This is a nasty one! It means that all 32 possible CDC_ACM serial devices (/dev/ttyACM25, etc.) have been used up.

The usual cause is using a serial port monitor and not closing it before restarting the board or uploading a new program. The operating system doesn’t like that, and locks up that device. After reset, the board comes back up as a new device. If you develop heavily and don’t restart, you’ll blow right through all 32 devices.

The lazy solution is to always close the monitor before restarting, and if you get this error in dmesg after a dfu-util “Not Found” error, restart you machine.

The hacker solution is to restart your cdc_acm kernel module. On Ubuntu 9.10, this goes a little something like:

$ sudo rmmod cdc-acm
$ sudo insmod /lib/modules/2.6.31-20-generic/kernel/drivers/usb/class/cdc-acm.ko

Tips and Tricks

Perpetual Bootloader Mode

In this mode, Maple stays a DFU device and does not jump to user code until the next reset. This is useful for guaranteeing that your Maple will be available for reprogramming.

To put your Maple (or other Maple board) into perpetual bootloader mode:

  1. Plug your board into the USB port.
  2. Hit the reset button (it’s the button labeled RESET). Notice that your board blinks quickly 6 times, then blinks slowly a few more times.
  3. Hit reset again, and this time push and hold the other button during the 6 fast blinks (the normal button is labeled BUT). You can release it once the slow blinks start.