Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: macdad- on July 21, 2010, 01:04:40 PM
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Hey guys, need some help with recommendations for a MCU. I'm experienced enough with microcontrollers after using the Basic Stamp, as well as other microcontrollers from studying manuals and such. My main problem is with development kits for the MCUs as I'm tight on budget, I was shooting for a MCU development kit that is $50 or less. I have been looking at the Zilog Z8 series as their dev. kit is roughly $40 at Mouser, but the Z8 MCUs themselves are somewhat low range on program memory(Only 1K). :P
I have still been looking around but to no avail. My main goals for the MCUs besides the $50 budget on the dev. kit are as follows:
- In DIP package
- Can work in the 5V range
- Atleast 8-Bit processor
- Atleast 1MHz Clock Speed
- Atleast 1 ADC
- Atleast 1 Timer
- Optional: Internal Clock Generation
- Optional: Supports C language
Help is appreciated,
Nick(macdad-)
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Arduino board:
http://arduino.cc/en/Main/ArduinoBoardDuemilanove (http://arduino.cc/en/Main/ArduinoBoardDuemilanove)
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- In DIP package
- Can work in the 5V range
- Atleast 8-Bit processor
- Atleast 1MHz Clock Speed
- Atleast 1 ADC
- Atleast 1 Timer
- Optional: Internal Clock Generation
- Optional: Supports C language
All your needs would be satisfied by ATmega48PA (PDIP-28, 4k + 512 + 256, $2.50), ATmega328P (PDIP-28, 32k + 2k + 1k, $4.50), or ATmega1284P (PDIP-44, 128k + 16k + 4k, $7.50), depending on how many extra inputs, outputs, ADC channels, and memory you might need. You can also buy an ISP programmer probably for under $20, so this seems to be a better option than Arduino if know how to solder and can download WinAVR + AVR design studio from the web.
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I second Razor on the Arduino recommendation. No other controller has a learning curve as small as the Arduino environment.
And to counter futmaci, realize you don't have to buy and Arduino, you can make one as well. Get an Atmega328P and a $20 programmer
http://www.pololu.com/catalog/product/1300 (http://www.pololu.com/catalog/product/1300)
and flash the Arduino bootloader to the 328. Now you have an easy to use Arduino at the same price with more usable tools left over.
I would also get a FTDI board, http://www.sparkfun.com/commerce/product_info.php?products_id=8772 (http://www.sparkfun.com/commerce/product_info.php?products_id=8772) as it can program Arduino using the bootloader, and is a nice USB <-> Uart board.
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Or the Baby Orangutan B328 http://www.pololu.com/catalog/product/1220 (http://www.pololu.com/catalog/product/1220) about $20. 32k program space. Lots of IO and ADC pins and 2 x on board DC motor controllers for small robots.
But the problem with all of these things: ie Baby Orangutan, Arduino etc is that you just want to plug a servo straight into the board - then you cant !!
If you are using a breadboard then this may not be a problem but if you want it to be standalone (ie no breadboard) then you need to create a simple board that converts their single signal pin output into a 3 pin header that can be used by a servo etc. For the Arduino these are called 'shields' but cost extra $.
The $50 robot, the Axons, etc have all these extra power pins as well - so you can just plug devices straight in without extra hardware/shields. The 'up front' cost is therefore higher but beware the hidden extra cost of using boards that don't supply the power and ground pins for each I/O pin.
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For the Arduino these are called 'shields' but cost extra $.
Not always true. My last post I was trying to make the distinction between the Arduino programming environment and Arduino the pre-built boards.
A Arduino board is pricey, but to flash a regular DIP Atmega 328P with the arduino bootloader gets you an Arduino IDE for less, and you can build your own board, and not pay for 'shields'. I learned that lesson recently.
But yes, if you want prebuilt with pinheaders, pony up $100 for the Axon.
OR
$50 for this Arduino (And you though Arduino didn't have servo headers!)
(http://www.curiousinventor.com/images/kits/roboduino/roboduino.jpg)
http://store.curiousinventor.com/roboduino/roboduino-assembled-servo-ready-freeduino-arduino-compatible.html (http://store.curiousinventor.com/roboduino/roboduino-assembled-servo-ready-freeduino-arduino-compatible.html)
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And you though Arduino didn't have servo headers!
Thats not what I said!
The Roboduino that you show has been supported by WebbotLib and its various Designer tools from day one purely because it DOES have the headers. And its designer is a SoR member. See - I did know that :D
But in the earlier posts you were talking about the Duemilanove and other 'duinos in general. None of which have this facility. Thats probably why Airman00 created the Roboduino in the first place.
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removed
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Wow y'all, thanks for your input and quick replies. 8)
The ATmegas look pretty good and I had a while back looked at them as an option but turned them down due to the price of the STK500, I didn't realize until now that the reason it was so pricey was because it had all the support components/power supply/demonstration pushbuttons/LEDs. The Arduino looks pretty slick too.
To save on cash(especially since I have to save up for motors), I'll probably go with the ATmegas as the soldering for the ISP programmer won't be a burden, the learning curve could be as high as it needs to be as I have programmed in ASM before(It was with the SNES processor).
I have read some other articles on the AVR studio, that it has a limited free programming or some other limitations for the free version for programming up to 4K(Or something like that), is that true?
On another note, the USB interface and pin headers with the Arduino(Roboduino) would make interfacing with various USB devices a breeze(I probably won't go that far though)
Thanks,
Nick(macdad-)
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I have read some other articles on the AVR studio, that it has a limited free programming or some other limitations for the free version for programming up to 4K(Or something like that), is that true?
I don't... think so? It's just a front-end for open source tools (such as GCC), also available in a command-line version as WinAVR. It would be rather unusual - and ultimately pointless - for any limitations to be put in place.
/mz
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AVR Studio is free and has NO restrictions. Your program can be as big/small as you like, and can be compiled for any ATmel AVR chip.
You 'may' also be interested in WebbotLib and its Project Designer. Both of which work with the boards already mentioned ie Roboduino, Baby Orangutan as well as the Axon. See http://webbot.org.uk (http://webbot.org.uk) for more info.
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But yes, if you want prebuilt with pinheaders, pony up $100 for the Axon.
OR
$50 for this Arduino (And you though Arduino didn't have servo headers!)
Not exactly a fair comparison . . . the Axon has *way* more IO, *way* more memory, and *way* more features. The Axon requires a single 6V battery, while the Arduino requires two: both a 7.2V battery for circuitry and at least a 4.8V battery for servos. And the Axon regulator is much more efficient, meaning you can get cheaper batteries. All this, and the Axon is still physically *smaller* than the Arduino. The WebbotLib library can't get any easier . . . And with built-in headers, its just plug-n-play. You don't need to fiddle around with loose wiring on a breadboard that can come apart at any time, buy $20 shields, or solder up your own.
The Arduino is designed to be ultra-cheap. And those who buy by price and not by features buy it. But sometimes its better to spend 2x more to get 4x more features :P
(I'm biased, if you don't already know ::))
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I'm looking at the ATmega88-20PU for about $3.50 at Mouser. Looks pretty good with 8KB of Prog. Flash, 512B of EEPROM, and 1KB of RAM with several Timers and ADCs running up to 20MHz! :o
It'll be simple enough for now since I'm not requiring any high-level processing with a Blackfin camera or such; as the most complexity I'll probably attain with it is just interfacing with other SPI Serial modules(external EEPROM chips, etc.), Admin does your Bluetooth module work with SPI Serial and/or USART?
The Arduino and Axon have some pretty impressive specs, but I like the fact that with a standalone MCU that you can wire up your own Regulator, OSC circuit, etc(Adds to the challenge of designing 8) )
Thanks everyone for your recommendation,
Nick(macdad-)
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Admin does your Bluetooth module work with SPI Serial and/or USART?
It connects using USART (we just say UART as shorthand).
The Arduino and Axon have some pretty impressive specs, but I like the fact that with a standalone MCU that you can wire up your own Regulator, OSC circuit, etc(Adds to the challenge of designing )
Understood. Buying a full mcu means its easy and reliable to use, but you don't learn all the fundamental details. To each his own :P