PICAXE in Computer

[computer]

Hi,

I am planning to build a custom circuit board for a homemade server I am building. It's a standard computer, and will run linux.
I have access to build proper PCBs at the local college, and I live in the UK - So I usually buy parts from Rapid Electronics, Maplin, or CPC.

Okay, so I was looking at the PICAXE controllers, (www.picaxe.co.uk) and they look pretty good. I want to do the following things with a picaxe chip, and if you can help me out with guides, circuit layouts, ideas, products, etc.

- Connect it to the ATX +5v standby power line so it is powered all the time the PC is plugged in.
- Have it light a tri-colour led orange (both green and red connected) all the time it is recieving power, and that an optoisolator connected to the mobos power header will be connected up to make the LED go green when the computer is on.... so basically, that bit runs in the background all the time looping, and it would work something like this:
(made up code language)

 if mobopowerheader is off, then light the green and the red output
 else, if mobopowerheader is on, then light the green output

- Have a key switch connected to it, which will control a red LED and an opto-isolator which is cutting into the mobo's power button circuit. code something like (runs in loop all the time):

 if keyswitch is on, then light the red LED and cut the power to the opto, so it stops the computer from being booted
 else, if keyswitch is off, then don't light the red led, and allow power to boot the computer

so, which PICAXE controller and external parts do you think I'll need? I think probably one of the 18X series would be enough.

Thanks,
computer

 

[computer]

Also,

how easy is it to connect a LCD display (1 line 20 characters) with a HD44780 standard controller to a PICAXE and get it to display hardcoded messages when certain inputs are high or low, or for instance to get it to show fan speeds or something from some software inside linux.

really I want it to say 'standby' when the computer is plugged in, but not swutched on. say 'booting' once the computer has started booting. then when it has loaded linux, it starts a program to rotate the screen from showing stuff like memory usage, fan speeds, temperatures, cpu load, etc.

possible? or is it better spending ££ on a Matrix orbital or something?

computer

 

[pike]

to build something like a computer will require a team of engineers. And person doing it solo sounds like your way over your head.

Seriously, do you think it is possible to build a computer from scratch?? Is it worth the money and time. for you maybe it is, but i thik you'll die before you finish the computer.

PICAXE is a microcontroller designed to help beginners learn the "BASIC" language. Not very efficient if your writing the program into the onboard eeprom of the chip...

If you still wanna go ahead with the idea of building your own computer,

Good Luck !!

 

[diode]

I am planning to build a custom circuit board for a homemade server I am building. It's a standard computer, and will run linux.

He never told he is projecting the all computer, what I understand here is "standard, home *assembled* PC", to which he wants to add this board.

 

[computer]

yea, I've been building computers for years... but in the sense of buying the motherboard, cdrom, processor, etc and putting it all together. I will be doing this into a custom 2U sized rackmount case... so I'm making a homemade server style thing...

 

[pike]

sorry, i assumed you ...yeah...

I would be careful with this sorta thing, you have to get all the finger alignements accurate, other wise it won't fit in the socket.

BTW: have you got the pin outs of the PCI socket ??

 

[computer]

okay, let me explain a bit better....

on the motherboards there are little pins which stick up, some of these already have wires attached, going to various places in your computer. others have not, and may or may not be connected to one of my custom boards. I am not sure what you mean by the finger alignments. I will be using din sockets on my boards to allow for easy soldering/replacement.

so, I want to know wether it is possible to control an LCD easily with the PICAXE chip, so it will do the following: I will probably be using one of the ones of the picaxe.co.uk site which you can buy.

say: STANDBY
TIME DATE

using the clock module when the computer is off but plugged in.

say: BOOTING
TIME DATE

using the clock module when the PC is first turned on, until thePC is booted correctly. when it has finished booting up, I want to be able to get the screen to show various system specs, from linux with control from the serial or parallel port, like you can do with a Matrix Orbital or similar display.

thanks,
computer

 

[pike]

Is it like a USB port ??

these wires sticking out of the MOBO should have 9 pins per socket if they are USB (Universal Serial Bus). 5 pins in one row and 4 in the other.

or do you mean something else ???

 

[computer]

hi,

don't worry too much about the computer interface part. but there is an onboard serial connector to drive the pic and lcd off if needed...

 

[Timmymna]

Computer did you solve this problem as I maybe able to help you as I've used PICAXEs before and seem to understand what you want to do with it.

 

[computer]

no not yet

i need someway of switching an LCD from picaxe control to serial control when a signal is detected down the serial line (ie, PC turned on and running a startup script, but gotta work out that one too)...

 

[Timmymna]

let me get this right you want to use a startup script on the pc to display "standby" "booting" etc and change the LEDs while the pc is off then once its on let the picaxe control it?

 

[computer]

not quite,

display shows time, and led is orange when power is only coming from a 12v supply (a transformer hooked into the iec inlet power supply so its there all the time the pc is plugged in).

when you press the power button, the motherboard will connect a signal to ground, whichg can be detected by the pic, and let the pic show booting and led green on the screen.

when the pc is finally got to linux, it will run some sort of script which will allow it to show things like the computer's temperature, fan speeds, memory usage and stuff on the LCD, like a Matrix Orbital style one can.... it can get this info from the serial or parallel port afaik

clear as mud?

 

[Timmymna]

I can only help a little as I've never tried anything like this but heres the basic program for the rest

This is needed to set the time of the real time clock on the LCD

start:

pause 1000
'Lets everything settle before anything starts
serout 0,n2400,(253,0,"14/03/04 23:00 ")
'Sets date to 14th March 2004 at 23:00
'24hr must be used and two spaces must be added
'so that the message is exactly 16 characters long
pause 1000
'Pause after write to LCD to set time
serout 0,n2400,(0)
'Displays time so check if was set correctly

end
'Ends program

Once that is programmed in you will have to reprogram with this


start:

pause 1000
'Lets everything settle before anything starts
serout 0,n2400,(253,10)
'Turns off alarm - Unsure if this is needed or notpause 1000
'Pause after write to LCD to turn off alarm
pins = 192
'Turn on the two outputs the LED is connected to (Pins 6 & 7 in this case)
'or
'pin6=1 'Which two pins the LED is connected to
'pin7=1
serout 0,n2400,(254,1)
'Clears the LCD
pause 30
'Pause needed while LCD settles after clear
serout 0,n2400,(254,128)
'Place the pointer at the first line first character place
serout 0,n2400,("Standby")
'Display "Standby" on the LCD - Pin0 in this case
serout 0,n2400,(0)
'Displays the current time and date on line 2
'Updated every 0.5 seconds
power:
if pin1 = 0 then poweron
'If power is on - Low
goto power
'Loop until power is low
poweron:
pin7=0
'Turns off the red part of LED
serout 0,n2400,(254,1)
'Clears the LCD of previous message
pause 30
'Pause needed while LCD settles after clear
serout 0,n2400,(254,128)
'Place the pointer at the first line first character place
serout 0,n2400,("Booting")
'Display "Booting" on LCDserout 0,n2400,(0)
'Displays current time and date on line 2
end
'Ends program

Thats all I can help with ATM, if I find anything I'll post it.

 

[computer]

i don't have any picaxe stuff at the moment, so do you suggest i go for the 18X starter pack with an LCD screen and timer module add on?

can you give me the links to the picaxe's shop site for what i would need?