Picaxe "Computer"

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ChedderCheeser

Senior Member
Hi all, I was jsut wondering if it would be possible to make a BASIC "computer" withg a Picaxe 40X2 as the "CPU". I'm thinking that I would jsut use a graphic lcd... if Its even advanced enough to make video like that... I would probably use another Picaxe to process the video.. idk.. I just think that it would be kino of cool to try to do... I've seen many TTL computers online... and.. Picaxe is TTL if im correct... so.. idk. Just a thought. What do you guys think? Is it at least a good idea? Is is possible? Where would I start? (reading the crap out of myself might help. if ya know what i mean)

Something a LITTLE kike this is cool, but probably not possible with a 4-32MHz cpu... 32 on a M2... but anyway, :
http://www.youtube.com/watch?v=Q5VLN5qa2_s
 
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C

ChedderCheeser

Senior Member
MartinM57 said:
2008'ish if I remember correctly...

http://chrisfenton.com/diy-laptop-v1/
http://chrisfenton.com/diy-laptop-v2/
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That is the coolest thing I have ever seen! I huess... I need a CPU, a I/O Processor, some eeprom, some speakers, a medium/large lcd, a case (hmmm....), and uh... batteries. And a voltage regulator. That look right? Also, if I used a 40X2, I would use the optional resonator for more speed. What do you think? The hard part would be programming... but the fun part would be plaing pong lol! :D Anyway, thanks for the link, and as ASKED before, that look right?
 
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srnet

Senior Member
ChedderCheeser said:
Hi all, I was jsut wondering if it would be possible to make a BASIC "computer" withg a Picaxe 40X2 as the "CPU".
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Maybe, however PICs\PICAXES are optimised for standalone single device operations.

Since the early days of the PC, Apple, TRS80, BBC Micro and the like these used Microprocessors optimised for use in bus based systems. The Microprocessor did the calculations and processing with data stored in other optimised devices on a data and address bus. Thus you could have large amounts of RAM or ROM for program storage and data manipulation, add specialised video handling devices, serial devices, audio devices, I\O control devices etc. Indeed a lot of 'computers' allowed the use of insertable expansion cards (on the data and address busses) to add more or better features.

Then you need an operating system of course.

A PICAXE does not have an (accessible) data and address bus, but no doubt you could try to simulate such things with a modern PIC\PICAXE, although adding a large quatity of high speed access RAM could be interesting.

Not sure about your referance to 'TTL', that normally referrs to 'Transistor Transistor Logic' a type of logic device. These devices have largly been replaced with lower power modern equivalents, CMOS, NMOS and the like.
 
C

ChedderCheeser

Senior Member
srnet said:
Maybe, however PICs\PICAXES are optimised for standalone single device operations.

Since the early days of the PC, Apple, TRS80, BBC Micro and the like these used Microprocessors optimised for use in bus based systems. The Microprocessor did the calculations and processing with data stored in other optimised devices on a data and address bus. Thus you could have large amounts of RAM or ROM for program storage and data manipulation, add specialised video handling devices, serial devices, audio devices, I\O control devices etc. Indeed a lot of 'computers' allowed the use of insertable expansion cards (on the data and address busses) to add more or better features.

Then you need an operating system of course.

A PICAXE does not have an (accessible) data and address bus, but no doubt you could try to simulate such things with a modern PIC\PICAXE, although adding a large quatity of high speed access RAM could be interesting.

Not sure about your referance to 'TTL', that normally referrs to 'Transistor Transistor Logic' a type of logic device. These devices have largly been replaced with lower power modern equivalents, CMOS, NMOS and the like.
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I meant like.. TTL voltages.. 5V and cmos: 3.3V .. right? Also, I LOVE the idea of Expansion Slots in this thing. As linked to above, the Diy Laptop v1 and 2 are nice and i MIGHT actually make v1.. there is no schematic for v2... :( But yeah. :D Operating system is the hard part. I would PROBABLy use a 40X2 as the CPU and a 8/14M2 as the "GPU" and maybe also the sound card... If I eventually make it with expansion slots and stuff... and i wanted an ethernet card.. would i use a Picaxe to process the ethernet or another chip? This is all talk.. but I am planning.. designing it when im lying awake in bed. :D I actually do design things like this in my sleep instead of think of the girl at school lol. Do you guys ever do that?
 
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srnet

Senior Member
ChedderCheeser said:
I meant like.. TTL voltages.. 5V and cmos: 3.3V .. right?
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Not quite, CMOS logic devices originally were for from 3v to 12v supplies, other CMOS devices designed to replace the TTL equivalents on 5V supplies.

Its true a lot of modern MOS stuff works on 3v3, but you have to look at it on a case by case basis, for instance whilst the PICAXE may be happy enough at 3v3 (and lower) and LCD module may need 5V level interface signals.
 
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ChedderCheeser

Senior Member
srnet said:
Not quite, CMOS logic devices originally were for from 3v to 12v supplies, other CMOS devices designed to replace the TTL equivalents on 5V supplies.

Its true a lot of modern MOS stuff works on 3v3, but you have to look at it on a case by case basis, for instance whilst the PICAXE may be happy enough at 3v3 (and lower) and LCD module may need 5V level interface signals.
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Oh. lol. Also, whatcha think about my ideas from above?
 
B

BillyGreen1973

Senior Member
ChedderCheeser said:
...... I actually do design things like this in my sleep instead of think of the girl at school lol. Do you guys ever do that?
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I think you'll find 'thinking of school girls' is not a socially acceptable pass time for most on the forum :D (most are 'over 30' shall we say)
Only kidding around, but as for thinking about projects etc, then yeah I would say we all have done that at some point. I would say, however, that getting the basics of the Picaxe system straight in your head, is a FAR better 'first project'.
Once you know what the Picaxe can and can't do, you'll have an easier time fitting a project around them.
In other words, start small, learn the structure, then expand on YOUR knowledge.
I would recommend getting a couple of books, Picaxe for the Evil Genius, and Customising the Picaxe. Both great books with good example projects that also explain the workings and step by step construction, well worth the read.
 
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ChedderCheeser

Senior Member
BillyGreen1973 said:
I think you'll find 'thinking of school girls' is not a socially acceptable pass time for most on the forum :D (most are 'over 30' shall we say)
Only kidding around, but as for thinking about projects etc, then yeah I would say we all have done that at some point. I would say, however, that getting the basics of the Picaxe system straight in your head, is a FAR better 'first project'.
Once you know what the Picaxe can and can't do, you'll have an easier time fitting a project around them.
In other words, start small, learn the structure, then expand on YOUR knowledge.
I would recommend getting a couple of books, Picaxe for the Evil Genius, and Customising the Picaxe. Both great books with good example projects that also explain the workings and step by step construction, well worth the read.
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Lol.. i just gave away my age. :D Anyway, thanks for that.. those books sound very interesting.. can I just download them, or do i need to buy them? Also, This project (if i dont find a better one) is one that I will PROBABLY be on for at least a year.. so.. yeah.. Plenty of time to learn. :D I am going to read the Picaxe Manuals. 1 a week. :D Wish me luck on that.. But yea, about the books.. can i download them or do i have to buy them?
 
W

westaust55

Moderator
@cheddar,
Can you please consider not quoting the entire post of the person you are replying to.
Either:
1. Use the post reply button at the bottom left corner more or
2. If there is a specific need to quote then use some editing and keep just the specific sentence you are responding to.
 
hippy

hippy

Ex-Staff (retired)
ChedderCheeser said:
I huess... I need a CPU, a I/O Processor, some eeprom, some speakers, a medium/large lcd, a case (hmmm....), and uh... batteries. And a voltage regulator. That look right?
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The first thing is to define what your computer is going to do, how you hope to use it and to what ends.

While admiring your enthusiasm ( IMO everyone should build a computer, even a CPU, some time in their life ) it may be a project which is a bit advanced for someone new to the PICAXE. Not so much that you couldn't do it, but with experience will come different insights which may change the direction of how you want or need it to be.

Take the I/O processor; an excellent idea for off-loading work from the main PICAXE, but how to do that, and how many ? I2C, serial, master-slave, P2P, star network, token ring ? Different options will suit different needs.

A 'computer' tends to be in the league of 'all things to all men' and it may be best to get a feel for what 'all things' may be with some more specific projects first.
 
C

ChedderCheeser

Senior Member
westaust55: Sorry about that. I will do that very much less often. Unless NEEDED.

hippy: I want it to do some BASIC text editing, maybe some music playing with a mp3 module, PONG!!!, tell time!!, uhm...be able to save text files, re-open text files to edit(DUH), um... But I want it to have its own language... I will call the language CHED++!!!!!!!!!!!!!!!!!!! Lol... But.. it has basic commands that get interpreted (i spell that right?) by the code on the CPU. The OS, is stored on a SD card. In this language, I would have commands such as these:

Do
While
Loop
For
If
Display
Music
Keyboard
etc...

For the I/O processor, hmmm.. good question... Depending on how I do this, If I were to make "expansion slots" I could use I2C correct? An I2C bus can have many devices at the same time RIGHT?
 
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srnet

Senior Member
ChedderCheeser said:
So... serial is faster right?
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Depends what you mean by serial, I2C, SPI, USB, Ethernet, Token Ring, RS232 are all interfaces where data is transferred serially, one bit at a time.

But they vary enourmously in speed, from about 115Kbits sec max (RS232) to about 100Gbits sec (Fibre).

Like Dippy says, it depends what you want to do.
 
J

Jamster

Senior Member
ChedderCheeser said:
I actually do design things like this in my sleep instead of think of the girl at school lol. Do you guys ever do that?
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Yep.

1) If you want to be able to use SD then the best option (unless you use Hippy's SD card 18x software) is the module from 4d systems: http://www.4dsystems.com.au/prod.php?id=22

2) I have tried to make my own interpreter out of a PICAXE however the 'if ' statements took a long time to code, also you end up with a microchip running an interpreter running an interpreter which slows things down dramatically.
Remember that if you ask VERY nicely, Technical (or other Rev Ed employee) may write you your own interpreter for PIC... ;) Possibly Dippy.

3) The idea of expansion modules is a very good idea however it may be easier to use the 28X2 baseboard, or (forgive me:eek:) the slightly more powerful A****** -due to the fact there are libraries to read SD cards etc. However i have never tried an A******and the code is a lot less readable/more difficult to write than PICAXE basic.

Hope some of this helps,
Jamster

P.S. Don't ask for the code, it got zapped by a virus...:eek:
 
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C

ChedderCheeser

Senior Member
I didnt think about that... A chip running an interpreter, running an interpreter... that wouldnt be good. Technical or other Rev Ed employee might right me my own PIC interpreter? Well, how much work is it to do that? I dont want to aks of too much... but, that would be VERY AWESOME! A chip with my own language... I can just inagine it... that... that would be sooooooo sweet. A****** ... I have seen things like this done with it and.. SADLY, I am thinking about making this project with one. (forgive me!) I have seen some of its code... looke... IMPOSSIBLE! But, if I coded it with MY interpreter and then used MY language to make the os... that might work... Have any of you a****** fans ever heard of the Pyxis OS? Its an OS that runs on arduino (and others?) Its very nice... i think i linked to it earlier... if not, lemme know. Im too "busy" right now, to find it and link to if. I wish i would've put it in favorites. Well, I think thats it... Picaxe WILL be in my NEXT project... It involves a ROCKET!!! I look forward to that. So.. a******. :( BUT, about having my own interpreter, can I make it myself if I learn enough or is it not... something I could do EVEN with a TON of practice and READING? Because that could come in havndy... Well, lemme know the answers to those. I'll update you on my decisions.

p.s. I BLEW UP my model car a few hours ago with fireworks. I must have used 500 AT LEAST firecrackers. What did you do fot July 4? Anything?
 
I

inglewoodpete

Senior Member
ChedderCheeser said:
... I must have used 500 AT LEAST firecrackers. What did you do fot July 4? Anything?
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Fireworks have been banned here for over 40 years. (but blowing things up sounds like fun!)

4th July? Shivered. Yesterday morning was the coldest day here so far this (southern) winter. I think you'll find that 4th July celebrations are culturally significant for residents of the USA and not so much for other parts of the world. January 26th is Australia Day.
 
C

ChedderCheeser

Senior Member
inglewoodpete said:
Fireworks have been banned here for over 40 years. (but blowing things up sounds like fun!)

4th July? Shivered. Yesterday morning was the coldest day here so far this (southern) winter. I think you'll find that 4th July celebrations are culturally significant for residents of the USA and not so much for other parts of the world. January 26th is Australia Day.
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wow. that kind of sucks... we cant do fireworks in town, but outof town... at the farm. :D
 
hippy

hippy

Ex-Staff (retired)
ChedderCheeser said:
Technical or other Rev Ed employee might right me my own PIC interpreter? Well, how much work is it to do that? I dont want to aks of too much... but, that would be VERY AWESOME! A chip with my own language... BUT, about having my own interpreter, can I make it myself if I learn enough or is it not... something I could do EVEN with a TON of practice and READING?
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You certainly could do it yourself; you first need to work out what the interpreted language will do and how the instruction set is represented, then work out how to implement that using a PICAXE. It's just like any other PICAXE project really.

I doubt Rev-Ed will do the project for you. We always give help and advice where we can but taking on complete user's projects would leave us with no time to do anything else ! There's a large PICAXE community and probably at least one who would be willing to help if you can capture their interest.
 
J

Jamster

Senior Member
@Chedder: The arduino is still an interpreter so it would just be an ATMega (I think) running an interpreter (A*******) running your Chedder++!!!

P.S. I presume that the final design will have a coffee cup holder ;)

P.P.S When I say ask Tecnichal, you may get a better response if you wave a £50 (or in your country $50) note.
 
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MartinM57

Moderator
Arduino code is not interpreted....the Arduino libraries are not that optimal but everything runs natively on the underlying AVR
 
D

Dippy

Moderator
To write Cheddar++ you will first have to write "Cheddar" - and that assumes you wish to follow the syntax of that ghastly C .
Most anoraks know why it's called C++ (WITHOUT using Google to be an expert!! Google-sight is 20/20 after all :rolleyes:).


Sounds like a fun idea. I think you'd better get on with it, no-one else will write it for you... though I suspect now that you have discovered how difficult it is then you might just go back to dreaming of the girl at school. :)
Good luck anyhow.
 
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boriz

Senior Member
I got it straight away Eclectic. That, the New quiz, the Now show and the Goons are some of my fave Radio stuff. Ying tong iddle I po.
 
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phillid

Member
Just thought I'd pitch in here and say that I'm going to make a picaxe computer like mentioned. I will be writing a few programs for it and I will be able to help Cheddar or anyone who needs it. I just need to wait until I can free-up one of my 18Xs out of another project :D. Shouldn't be more than a week.

Anyone know where to get really cheap serial LCDs around 8 lines by 20 chars (preferably in New Zealand).

Kind regards,
Phillid
 
C

ChedderCheeser

Senior Member
phillid, did you look at the diy laptop? Linked to at the SECOND? post. Maybe i'll make that since it already has a schematic AND code. I wish there was a schematic for the second one... oh well. About the lcd, idk... I go to sparkfun, but thats probably not where you wanna order from.

All:
Whats with the names and ???'s? lol../.
 
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