xtremefist23:
Can anyone cite any disadvantages for Arduino Mega 2560? We just need to have these information for the comparison of Microcontrollers for our project study. Thanks in advance!
Disadvantages? How much time do you have?
Mounting holes placed so that they are unusable.
No keep-out for the mounting holes, resulting in the need for insulating washers if you do try to use the mounting holes.
CPU is clocked with a temperature-unstable ceramic resonator instead of a crystal. (I REALLY would not mind paying an extra dollar for a dang crystal!).
No footprint on the board in which TO install a crystal if one wanted to (for example, USE a crystal or change the clock frequency, etc..)
Three of the five input capture pins are not connected to any IO connectors, making them useless.
Horrible 16u2 USB to Serial adapter (pukes anything above 115K baud). What was wrong with the FTDI?
Many 8 bit ports mish-mash connected to various places, making it difficult to find and use a contiguous 8 bit port for parallel writes and reads.
Pathetic little 5 volt regulator on board that overheats if it even THINKS about incoming voltage over 9.0
Not enough VCC and GND pins, invariably forcing the user to make special adapters to power added-on peripherals.
Terrible stock bootloader. The actual bootloader fits in 2K with room to spare, but it's clogged with over 6K of code providing a "monitor" that nobody uses and actually causes lockups if code or user input happens to contain the magic "!!!" string used to access it.
Everyone whines that "floating point libraries cannot be used because they consume an extra 1.5K of flash", but the wasted 6K of flash containing the unused monitor is OK? Go figure.
Serial bootloader and serial monitor are on the same port (even though the Mega has 4 UARTS (forcing the user to manually close the serial monitor before uploading another sketch if they use a real serial emulator instead of the barely functional one built into the IDE). Worse yet, forgetting to close the monitor usually causes the OS to think the current port is in use and it switches to another one, leaving the user wondering why he sees no more serial data.
There is a lot more wrong with the whole system (the terrible "IDE" for example), but that doesn't relate specifically to the Mega, so I won't go into it.
On this note....... does anyone know of a board that contains a MEGA2560 CPU, a crystal and an FTDI interface? (Doesn't have to be Arduino footprint compatible - in fact it it were footprint compatible, that would be a negative feature).
I spend way too much time hacking Arduino boards to get them to work properly... I need to find one that is "right" out of the box so I can get on with PROGRAMMING.