How many of you have built a Microcontroller?

[VladKEasternTiger]

Hi Gang, im wondering how many of you guys and especially the experienced people have build a Microcontroller device or a remote control device? I had watched a video on Youtube about a university in the UK on a EE course programme and in their final year they build a Microcontroller

Im wondering how advanced would you need to be in Electronics to master this area or a remote control device, I presume it takes a lot of knowledge.

[migsantiago]

More or less.

I built a PIC16 clone on VHDL. It's kinda tricky because you have to know how a pic works... its ALU, ram, buses, rom and program counter. Then you have to know how instruction codes operate and how to receive and process bits.

It's not that hard, it just takes time and effort.

At the end, I prefer using microcontrollers instead of designing them.

[joelby]

Designing a very simple microcontroller in VHDL seems to be a fairly common 3rd/4th year engineering course.

Remote control devices are easy to build with off-the-shelf transmitter and receiver modules. To design a complete radio system is a little bit more involved - it seems like few people bother these days, and why would you, unless you had advanced requirements and unlimited free time?

[VladKEasternTiger]

How would I get an off the shelf receiver transmitter model? Do you mean buying like a cheap remote control toy car and taking the transmitter receiver out of it?

[TheDirty]

Sparkfun sells plenty of transmitter/receiver modules.  They range from the dumb on/off units that require you to do your own encoding to super smart mesh network transceivers that do everything for you, like the XBEE's.

I've played with a whole range of them from the dumb transmitter/receiver modules to the transceivers like the CC2500 which are IEEE 802.15.4 compliant, but lately I've been using the HopeRF RFM12B modules, which are kinda between the dumb modules and the super smart modules.  You talk to them over SPI and they have some nice features, but it's still pretty simple and you can implement your own protocols.

Actually, if you are using an Arduino (I don't) there's code available already for the RFM12B's and this guy does a lot with them:
http://news.jeelabs.org/

Dumb modules:
http://www.sparkfun.com/commerce/product_info.php?products_id=8949 Receiver
http://www.sparkfun.com/commerce/product_info.php?products_id=8946 Transmitter

RFM12B:
http://www.sparkfun.com/commerce/product_info.php?products_id=9582

XBEE's:
http://www.sparkfun.com/commerce/product_info.php?products_id=8665

[fsleeman]

I designed a pipelined MIPS processor using VHDL in college but unless you have a really specific need there isn't any reason not to use an existing microcontroller. You do need to have a working knowledge of computer architecture and digital logic design to attempt such a project.

For remote control you could either use the IR receivers/transistors that would compatible with protocols used by common microcontrollers, or you could use a radio model over RS-232.

[migsantiago]

Sparkfun sells plenty of transmitter/receiver modules.  They range from the dumb on/off units that require you to do your own encoding to super smart mesh network transceivers that do everything for you, like the XBEE's.

Hi TheDirty, why do you call those modules as "dumb"? Is it because they're foolproof? 

[TheDirty]

Because there is no logic built into them at all.  All you get from the receiver is an on/off signal.  It's not a clean on/off signal either, the on/off signals have to be 'dc balanced'.  You can't just leave an on signal otherwise it decays.  So with the 'dumb' modules you need to do all the logic for encoding and dc balance yourself.  When I used them I stole code from an Arduino library called VirtualWire, which is pretty nice.  All it needed for it to be used with my uC was a timer running 8 times the data rate.

These 'dumb' radio modules are not worth it anymore.  The price of both transmitter/receiver is over the cost of a single RFM12B module.  The receiver alone costs almost as much.  I got my RFM12B modules directly from HopeRF a while ago.  You still should be doing your own encoding with the RFM12B's, though.  If you want everything done for you, you have to spend the extra money on the XBEE's.

[septer012]

Better:

http://web.cecs.pdx.edu/~harry/Relay/

[migsantiago]

Better:

http://web.cecs.pdx.edu/~harry/Relay/

Wow, that's true effort. It looks as if he had built it in his bedroom, hasn't he?

http://web.cecs.pdx.edu/~harry/Relay/index-Pages/Image5.html

[GeekGirl]

I could turn straight for a man like that a relay computer in my bedroom

[Simon]

I always dreamed of creating my own computer but then got realistic and learn to live with windows

[Zero999]

I always dreamed of creating my own computer but then got realistic and learn to live with windows

Or you could just buy a PC and install another OS, Linux, BSD or even get a hackintosh.

[Simon]

I was young and thought I could do great things, I think I thought making my own world was easier than learning to use what was current, but then i was always useless with programming like stuff and gave the mere idea up

[migsantiago]

I could turn straight for a man like that a relay computer in my bedroom

LOL, you're so geek 

[embedded]

I think he meant micro-controller based board.  Built a lot of those.

I built a stepper motor controller once with a SEEQ EPROM address latches and phase data coming out but did not build an ALU all the way.   Although I worked on a 8080 implemented with 74 series ALU and micro-controller we had for a project.  So we were the first on our block in Waterloo Canada to have a MMU to address more than 64K.

The craziest one was with 4 phase P Mos in 197X we had a 8 kbyte romulator made with 7474's.  We loaded it up with a PDP-11 then would send the rom with peripheral out to fab.

But I designed a number of application specific standard product with Altera and Z8650 core to be made into real Z8 micro-controller with peripherals.  Now you do the whole thing in an Altera or Xilinx FPGA like Dave has described.

The whole thing is to understand what the system has to do, what the technology is capable of doing with obtainable parts, blocking it out, selecting parts, assigning functions to pins then completing the design and coding it.

[VladKEasternTiger]

You obviously know your stuff, what do you do I presume you work with electronics or in a related field?

p.s is waterloo in Kitchener? I visited Kitchener canada

[monstrum]

I built a processor with discrete logic once back in High School. It had something like 20 instructions. Could address 256 bytes of RAM (which I didn't build myself though).

[coreyc]

I'm currently on a multi-disciplinary design team in my senior year. I've had some exposure to Microcontrollers through a semester long class in which we worked on a team to design/program a project of our choosing. Lots of cool stuff. MIDI Controllers, Synthesizers, etc. I'm currently using a Texas Instrument MSP430 due to its two internal clocks. I'm on a team that is designing an air switching value for the next-gen space suit - really cool stuff.

Programming Microcontrollers just takes practice but there are some awesome applications. I wish some engineering programs introduced this stuff earlier. I'm sure it would prevent the massive drop rate from the EE major at my school. 

[EEVblog]

I could turn straight for a man like that a relay computer in my bedroom

You're too easy! 
At least hold out for glowing valves and nixie tubes!

Dave.

[jimmc]

You're too easy!  
At least hold out for glowing valves and nixie tubes!

Dave.

Like this?
or this

Jim

[hans]

For school we had to simulate an ALU with VHDL before. It was very simple, 4-bits, just a few slices to link together + the slice to make for a few operands. Things included like OR, AND, XOR, Rotate and Shift. Nothing special. Nothing to do with memory.

It's a very interesting challenge, but I don't think I would have to patience to hold out on such a long simulation trial.

[wd5gnr]

I'm not sure if you mean built something WITH a microcontroller or built a microcontroller (which is what most of the thread seems to focus on).

This is my "one instruction wonder" in Verilog: www.drdobbs.com/embedded-systems/221800122
There's a newer version at: http://www.one-der-cpu.info/ (log in as guest if you like).

I also did a 16-bit Verilog implementation of Caxton Foster's Blue (with lots of enhancements): http://www.opencores.org/project,blue -- the Video on that page shows the cool front panel which is actually slicker than the CPU. OpenCores has lots of designs for CPUs including http://www.opencores.org/project,mcpu which is about one page of VHDL or Verilog and fits on a CPLD!

Al W.
http://www.awce.com