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Optical drive interfacing

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Hi Everyone,

I will be later trying to interface either a hard drive or floppy drive to a PIC but will be trying to do it first on a pc parallel port. However i have searched quite a bit to find and websites or datasheets talking about how to do this. does anyone know how you do this ir can point me in the right direction. I do want to use the parallel port first because it is much simpler to program. Im guessing a floppy drive is simpler to do.

Thank you for reading this everyone
 

Nigel Goodwin

Super Moderator
Most Helpful Member
You would be wrong to think so!.

There are many examples of interfacing IDE drives to a PIC on the net, but as far as I'm aware there are no floppy examples at all, it requires too much RAM.

However, this is the 21st century, it makes more sense to interface an SD drive, which uses a simple SPI interface, and a LOT less pins.
 
yeh iv'e thought about using sd cards but i don't have any spare at hand and i don't know why but if i were to interface a hard drive/floppy drive to somthing it would feel a great achevement. i was thinking of a kinda ebook project using a character lcd but i will figure that out if i do get to interface a drive.
 

Papabravo

Well-Known Member
There are very few designers left who can design a FDD data separator. You should pick up a FDD manual and see if you can get your arms around even starting to do an interface. I'd be surprised if you could. A biphase mark encoder for the write chain is fairly easy, but the decoder is just a bit more difficult.
 
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Sceadwian

Banned
Buy one =\ You can buy them at most gas stations nowdays... At least 1 gig for 20 bucks, and that's on the steep side.
 
ok i'll have a look later. thanks. the only other problem is what should i use a connector to interface the card. ive heard that they are hard to find but somone has used a 5.25 inch floppy connector. i however used to have one of those cables but lost it. do you know where i can get a sd/5.25 inclh floppy connector from. does anyone know of any good tutorials to interface an sd card. thanks
 

Sceadwian

Banned
Not hard to find at all anymore, just off the top of my head sparkfun.com sells both SD and microSD breakout boards for about 15 dollars. I'd get a full sized SD carrier because you can get adapters that convert micro SD to full sized SD formfactors if needed. Sparkfun has several links with all the information you need on how to access SD cards. While using an old Floppy drive has a bit of nostalgic value to it, it's really so outdated and difficult to use compared to modern hardware that it's not worth anything but as scrap metal.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
While using an old Floppy drive has a bit of nostalgic value to it, it's really so outdated and difficult to use compared to modern hardware that it's not worth anything but as scrap metal.

It was discussed on the PICList years back for a LONG time, and as far as I'm aware no one ever managed to do it? - and really now it would be incredibly pointless, they hold so little data.
 
ok i got an sd card just now from my local superstore which is a 1 gig sd card. i find it easer to program the serial and parallel port on my computer so is it possible to try my card out on those first and learn to interface my card that way. if i can do it i will then goto the pic chip. i'll have a look on sparkfun now. thanks for all help
 

Sceadwian

Banned
If you're just testing it you dont' need the breakout board, you just need aligator clips that will make good contact with the pads on the card. Check out Google you'll find code on how the protocol works, should find working PIC code as well. If I'm not mistake it's 3.3v though so you have to do level conversation or you could fry the SD card. It's a static serial protocol so I guess you could interface it with a parallel port if you level adjust it.
 
how do i do that. i perfer doing digital programing with pic chips and using things like paralell port and interfacing. im not so intrested in things like voltage conversion
 

Sceadwian

Banned
I'm not sure if you understand. PIC's typically run on 5 volts. SD cards run at 3.3 volts, you HAVE to convert the signal and power lines to 3.3 volts or the SD card will be damaged. The easiest solution is to run your PIC at 3.3 volts then everything is happy. If you need to run your pic at 5 volts for some reason you'll need a seperate 3.3 volt regulator for the SD card and some way to convert the 5 volt output's of the PIC to 3.3 volts, the 3.3 volt signals that the SD card puts out will be able to be read directly from a PIC I/O line but not the other way around, for the data lines this could be as simple as a voltage divider.
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
how do i do that. i perfer doing digital programing with pic chips and using things like paralell port and interfacing. im not so intrested in things like voltage conversion

Check this PIC example, which shows how to interface 3.3V to 5V.

If you're doing it from a PC you need to use the parallel port, not the serial one, and have direct pin access to the port (much like writing PIC programmer software).
 
sorry been busy in school. sorry but i cant seem to find the link to where the tutorial is or is it the link in your sig
 
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