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Author Topic: What is the best option FPGA board or a Microcontroller board  (Read 5388 times)

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Offline tamaTopic starter

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What is the best option FPGA board or a Microcontroller board
« on: January 24, 2008, 09:24:00 PM »
Hi Guys

Pls help me in selecting a fpga/microcontroller board. I am want to develop a robot/tank(not yet decided). which should be able to control 4-6 servo motors, sensors, RC interface initially and later add some image processing to it. What do you recommend for such a project, should i go for a FPGA board or a MICROCONTROLLER board. Most of the standard fpga development boards are pretty big in dimensions... I came across xilinx virtex4 board Xilinx Virtex-4 FX12/ Spartan 3 Mini-Module which supports power PC also. This board cost 250$ and based board cost 195$. Is this board satiable for the application i mentioned. Do you thing it is worth buying this board.

for a microcontroller board what kind of microcontroller should i look for, 16bit, 32 bit. Guys pls give me some leads. Guys ur opinions would help me selecting the board.

Thanks in advance
Tama

Offline SmAsH

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Re: What is the best option FPGA board or a Microcontroller board
« Reply #1 on: January 24, 2008, 09:27:31 PM »
if you know your programming basics i would go with microcontroller its the most common and you can find lots of help if you get stuck with anything.


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Offline tamaTopic starter

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Re: What is the best option FPGA board or a Microcontroller board
« Reply #2 on: January 25, 2008, 12:54:42 AM »
i have done programming in C/VHDL at my work place so i am, kind of used to both of them. the main thing which i am a bit confused is that in fpga there are several IO lines so u can connect n no of devices to it and control them in parallel. where as in a microcontroller, there are limited no of IO hence limitations on interfacing ( thought it is not a big issues, i guess for this project). Also in microcontroller its not exactly parallel processing( virtually it is because of its speed).

Apart from this there should be flexibility for future enhancements/ modifications.


Offline dunk

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Re: What is the best option FPGA board or a Microcontroller board
« Reply #3 on: January 25, 2008, 10:42:31 AM »
hi Tama,
so please bear in mind i have never used a FPGA so please don't take this as anything more than my opinion.
so generally FPGAs are better than microcontrollers when you need to keep track of multiple signals with good precision.
microcontrollers are better than FPGAs when you want a (relatively) easy to program and inexpensive solution.

as the only timing critical part of what you are talking about is 4-6 servos and a bit of serial data transmission this can easily be accomplished on a microcontroller using interrupts.
as your project grows (as robot projects tend to do as you get more ideas) you may need to decide whether to network multiple microcontrollers or again look into an FPGA
but for your current requirements i would recommend a microcontroller.

as for which microcontroller,
it has been asked many times on the forum and received many different peoples opinions.
at the end of the day there is no easy answer. decide if you want to make a board from scratch or buy one ready made then pick one with the features you require.


dunk.

Offline Admin

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Re: What is the best option FPGA board or a Microcontroller board
« Reply #4 on: January 25, 2008, 05:43:13 PM »
This should help:
http://www.societyofrobots.com/robot_faq.shtml#best_microcontroller

FPGA's are best for intensive parallel processing. They are a bit difficult to use because of a very small user base to help you with it.

If you are trying to build a basic robot, a microcontroller would be better (easier and cheaper) for you.

Offline tamaTopic starter

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Re: What is the best option FPGA board or a Microcontroller board
« Reply #5 on: January 25, 2008, 11:50:44 PM »
Hi Guys
Thanks for ur replies... dunk as you have mentioned about making a board itself.  I have some ??? in regards to it. I would prefer to do programming in C...

1)if we make our own board then we would need to write our own OS is this correct. I can make the board thats not a problem, but i have never written a OS for such a thing. If we get a board readymade then we do get IDE and its basic OS.

2) what are the basic things in a microcontroller i should look for.. serial ports, ADC interface, memory. etc...

3) now a days 32bit microcontrollers are pretty cheap, so it best to go for it.

Guys i am bit new to microcontrollers hence so many ?? ur opinions would really help a lot.

Thanks in advance
Tama


Offline dunk

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Re: What is the best option FPGA board or a Microcontroller board
« Reply #6 on: January 26, 2008, 05:28:10 AM »
Quote
1)if we make our own board then we would need to write our own OS is this correct. I can make the board thats not a problem, but i have never written a OS for such a thing. If we get a board readymade then we do get IDE and its basic OS.

nope.
you'll only need an OS if you are wanting to do very fancy things but a microcontroller can run a single program without needing an OS.
you will need a compiler, programming language and libraries for your programming language.
compilers, programming languages and libraries tend to be written for the microcontroller rather than the development board.
as an example, a lot of people on the forum use AVR microcontrollers.
there is a GCC port available for AVRs. once you get a programing environment working for AVRs you will be able to program any AVR based board using it.

Quote
2) what are the basic things in a microcontroller i should look for.. serial ports, ADC interface, memory. etc...

yup. most basic microcontrollers will have the functionality you have described. for your reference a microcontroller will only implement a logic level serial port (ie. +5v) and will be called a UART (or USART) so will need a little extra circuitry to connect it to a PC serial port.

Quote
3) now a days 32bit microcontrollers are pretty cheap, so it best to go for it.

to be honest, as a first project i wouldn't worry too much about the raw power of your microcontroller. it makes little difference for simple projects.

Admin talks microcontroller Noobs through the basics in his $50 robot project: http://www.societyofrobots.com/step_by_step_robot.shtml
whether you choose to build it or not it would be good background reading for you.


dunk.

Offline pomprocker

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Re: What is the best option FPGA board or a Microcontroller board
« Reply #7 on: November 12, 2008, 12:49:53 AM »
FPGAs loose their functionality when the power goes away (like RAM in a computer that looses its content). You have to re-download them when power goes back up to restore the functionality.

FPGAs are RAM based. They need to be "downloaded" (configured) at each power-up. CPLDs are EEPROM based. They are active at power-up (i.e. as long as they've been programmed at least once...).


 


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