Datasheet

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6 Frequently Asked Questions (FAQs)
Some questions you may ask and the answers.
avrdude: AVR device not responding
Q: When I try to program the device I get an error: "avrdude: AVR device not responding."
A: The most likely cause is that you have forgotten to place the four programming jumpers.
See section 3.2 Program the Atmega-328.
Why is my program slow?
Q: When I run the program it is very slow. Where I expect a delay of 1second it takes much
longer.
A: Straight from the factory the CPU runs from the internal 8MHz clock and that is divided by
8. Thus the processor runs at 1 MHz. To switch to the full speed, using the external 16MHz
oscillator run the avrdude command as described in 8.1Atmega-328under "Initial clock
setup"
Why does my program not run?
Q: When I upload the program it runs fine but when I halt the Raspberry-Pi or when I start the
Raspberry-Pi my program does not work.
A: GPIO 8 controls the Reset of the Arduino. This pins must be high but for your program to
run. The simplest solution is to remove the programming jumpers. Alternative is to program
the GPIO-8 pin high using the reset_off script. The avrdude with the -c gpio option does this
for you so normally after programming the reset has been removed.
I have a different compiler
Q: I use the AVR compiler on my PC. How do I program the Atmega on the Raspberry-Pi?
A: I have only experience with the GCC version (AVR 5.1 and higher). After compilation you
find a .hex file in the debug directory. You have to transfer that file somehow to the
Raspberry-Pi and use the programmer script Program 328 as described in 8.1Atmega-328
to program the device(s) on the GertDuino. (If you have the script already installed use
"./program_328 <hex file>)
The Raspberry-Pi boots different: it has big text and not the normal prompt!
Q: When I plug the GertDuino on the Raspberry-Pi it boots different: It has big text and not the
normal prompt!
A: Pin 5 of the GPIO connector is used to indicate ‘safe boot mode’. If that pin is low when
booting the Raspberry-Pi boots in “safe mode”. Pin 5 is also connected to the Atmge-48. It
is one of the I2C pins. Thus if your 48 is driving a LOW on that pin the Pi always boots in
safe mode.
To prevent this you can put “avoid_safe_mode=1” in the config.txt file and the pi will boot
normally.
Why is there no battery supplied
Q: The GertDuino has a battery holder but there is no battery in there. Why do I have to buy
my own?
A: These batteries are lithium batteries. Those are classified as ‘Dangerous Goods’ and
require special paper work, warning labels and other precautions when shipped. And that is
for shipping within the UK. International shipping becomes a nightmare. So we decided to
leave it off.