Electronic – Atmel chip come with bootloader

atmelmicrocontroller

I would like to know if Atmel microcontrollers come with a bootloader. For example I asked a question earlier where other users were saying that a microcontroller could be used instead of a 555 timer which is old.

I realise you can create a delay by programming the chip using AVRstudio?

Basically do they have a bootloader or libraries installed that run this code or do you need to install it yourself?

Best Answer

Some do.

From personal experience, I can tell you the ATMEGA32U4 has a USB Bootloader from the factory.

Personal experience aside, this list from ATMEL is more complete.

You can use whatever you want to actually compile the code into a hex file. (ie AVR Studio).
You will then need to use ATMEL's FLIP uploader to program your chip.

Fresh from the factory, the chip will be in "programming mode", ready to accept your file.
If you want to change the program after initial programming, you can put the chip back into "programming mode" by grounding the HWB pin and toggling the RESET pin.

In your circuit, the HWB should be "pulled up" via a resistor to VCC. That way, the pin is not left floating and you will not put the chip into programming mode accidentally.

Related Solutions

Watchdog enables itself after reset

Following is stated in page 615 of the reference manual, under section 23.3.2:

The new configuration takes effect only after all registers except WDOG_CNTH:L are written once after reset. Otherwise, the WDOG uses the reset values by default. If window mode is not used (WDOG_CS2[WIN] is 0), writing to WDOG_WINH:L is not required to make the new configuration take effect.

Adding these lines in initialize_CPU() function under file init.c, I can configure the watchdog timer, and disable it:

WDOG_CS1 = 0x60;
WDOG_CS2 = 1;
WDOG_TOVAL = 0x04;

Also, it is good to note that watchdog timer registers are write-once only. So, individual bit changes are not going to have an effect after first write to the same watchdog timer register.

If user wants to configure any of the watchdog timer registers later on, updates should be enabled in the first configuration. After that following is used to configure watchdog timer the second time. For more information, please have a look at the reference manual.

/* Initialize watchdog with ~1-kHz clock source, ~1s time-out */
DisableInterrupts; // disable global interrupt
WDOG_CNT = 0xC520; // write the 1st unlock word
WDOG_CNT = 0xD928; // write the 2nd unlock word
WDOG_TOVAL = 1000; // setting timeout value
WDOG_CS2 = WDOG_CS2_CLK_MASK; // setting 1-kHz clock source
WDOG_CS1 = WDOG_CS1_EN_MASK; // enable counter running
EnableInterrupts; // enable global interrupt

Searching for a programmable microcontroller (USB & LED dimming)

Arduino IS based on a microcontroller (by atmel) and is basically a breakout board for such microcontroller plus some friendly way to upload a program to it.

It's programmable in c++ so it's quite easy and, as @Michael said, the community is huge. You can use the program on a bare chip without the board if you provide the proper connections, parts etc...

That said i'm a PIC user and i don't really like the bulkiness of arduino (both in terms of price, physical space and memory occupied by the bootloader) and the way its community works.

BUT if you want to program a pic or an avr you need an external not-so-cheap programmer (search for pickit2 or avr dragon...way more than an arduino) and a proper c compiler. Then remember that usb access comes at a price (i.e. writing a program to use it but then you need a way to program the chip in the first place!).

Arduino has everything you need to start FAST and such a program would be nearly trivial with all the libraries, a thing i wouldn't dare to say for a "from scratch" project like yours. Then again, if you want to learn bare embedded programming just grab a micro, buy or build a programmer, download the tools and start by blinking a LED then build from that. I'd advocate for PICs but really it doesn't matter. AVRs have nice open source tools while PICs are slightly cheaper. You'll find hundreds, thousands of discussions on which is best and why they're wrong :P

Best Answer

Related Solutions

Watchdog enables itself after reset

Searching for a programmable microcontroller (USB & LED dimming)

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