How Hard to Use Floppy For Flasher?

[Nigel Goodwin]

I don't see why you are having this conversation.... A pic16f877a or equivalent.. with a FD controller chip and a 23k256 SPI sram.... Job would be relatively easy..

If it was 'easy' why was it never done?

Although adding two extra chips to make it possible isn't really 'easy', certainly not compared with interfacing an SD card.

As I've said, it was discussed endlessly on the PICList, by people FAR above my capabilities.

 

[Ian Rogers]

Years ago..... I put an old 5 1/4 360k floppy on my BBC .. Granted the software was available on the bulletin boards "ADFS". It was Cumana adapter the hardest part would have been the software..... The ONLY restriction on the pic's is the buffers for the FAT tables and sector buffers..... It is basically the same as the SD project was working on... The VDrive stopped me finishing the project.... It was an easier / less expensive solution.

I have also succeeded in fitting a floppy on the old Z80..


Reading through the reasons no-one has succeeded... They were making an interface... This IS impossible, well nearly. The read frequency is very high.. To high for the humble pic..
The others gave up because the Floppy disk controller was increasingly harder to track down... The intel FD controller was integrated with the main IO on the early AT PC's
I tried to buy a WD1797 years ago ( for my speccy ) ended up getting a manufacturer PCB from a little computer / electronic shop here in Oldham... This is why I would NEVER attemp to make another one..

 

[ChrisP58]

I don't see why you are having this conversation.... A pic16f877a or equivalent.. with a FD controller chip and a 23k256 SPI sram.... Job would be relatively easy..
Or even a 8051 derivative connected to a 32k memory chip..

BUT WHY!! I didn't even think you could buy Floppy disks any more... As was previously mentioned... Extremely unreliable, outdated FAT14

You would be better using your time connecting SD card to a small pic and the 32k SPI sram....

Just my take...

Maybe someone has a container full of surplus floppy drives they're trying to find a marker for.

 

[dougy83]

the issues is that a few dozen bytes of GPR's isn't enough to run a floppy.

Many PICs have far in excess of "a few dozen bytes of GPR's (sic)". How many bytes exactly is "enough to run a floppy". The filesystem normally used on a floppy disk (FAT12) is less resource intensive than that used on larger hard disks (e.g. FAT32). There are a number of projects (e.g. MP3 players) that use a PIC to read from a hard disk drive. Arduino makes use of a FAT16/32 library that will run on an ATMEGA168 (1kB RAM), again proving that it is very possible to access a filesystem even on a small microcontroller.

I don't see why you are having this conversation.... A pic16f877a or equivalent.. with a FD controller chip and a 23k256 SPI sram.... Job would be relatively easy..

As the OP is just wanting to read from the floppy, it makes it even easier. After finding the file to load and getting a small array of clusters to read it is just a case of seeking and reading the appropriate tracks and sectors. From what I've read there isn't even a need for the controller chip; just decode the MFM directly using the PIC.

If it was 'easy' why was it never done?

Perhaps you should explain the reasons that these nameless PIClisters failed to get it working; you're the naysayer.

Reading through the reasons no-one has succeeded... They were making an interface... This IS impossible, well nearly. The read frequency is very high.. To high for the humble pic..

The data comes in at 500 kbps. This should not rule out PICs. If data is missed, it can be read on the next revolution.

 

[Ian Rogers]

Hey Dougy... I'm not saying it can't be done... I think it can... I'm saying WHY!!! The OP wants to use it as a flash device... A pickit2 is only £24.. The WD1729 will cost him about that.. It requires a dab hand at assembly to create the software for the project.... A mans got to know his limitations!!!!! ( Clint Eastwood Dirty Harry )

I'm just being realistic....

 

[atferrari]

I notice many microcontroller projects actually use the serial, Parrallel, or USB for the Data transfer and Flashing Process... My question is:

How much trouble would it be to have the PIC read its info from a standard Floppy drive? Therefore, you could copy your Programs to floppy disk and use the disk to flash the Microcontroller (PIC).

Would make your PIC more mobile... Is this a problem creating?

A programmer where the program to be burnt into the PIC is in the disk.

Who would be in charge of the burning?

Just in case, take a look here and see what this guy did, albeit much more complex. Its is a HDD.

 

[ghostman11]

thanks for the link atferrari very interesting read!

 

[voidptr]

A 6809 ISN'T a micro-controller, it's a fully fledged micro-PROCESSOR, with access to up to 64kbytes of RAM - while a PIC is faster than a 6809, that isn't the issue, the issues is that a few dozen bytes of GPR's isn't enough to run a floppy.
A 6809 was commonly used with floppies. that's the era (and before) that floppies came from.

Im so sorry all those years i thought those microcontollers can steal job from those super powerful old micro processors !
Thanks for you enlightful comment !

lol Again im pretty sure we can do it , 10 years ago probably not ... memory size was a limiting factor but take a peek at those Microchip 23A1024
SPI is not so slow after all. Put that with a Pic ( or other microCONTROLLER) with DMA channels ( microchip has even few 18F with them .... let see something like PIC18F44J11 ) and you can have something that might work

 

[Nigel Goodwin]

Im so sorry all those years i thought those microcontollers can steal job from those super powerful old micro processors !
Thanks for you enlightful comment !

You thought wrong then

Why doesn't your PC run on a PIC if that's the case

A micro-controller is a small, cheap, fast, replacement for a micro-processor PLUS a large number of support components - essentially it's a complete computer on a chip. In order to make it 'cheap' large quantities of RAM aren't provided, as it's very rare you need them.

lol Again im pretty sure we can do it , 10 years ago probably not ... memory size was a limiting factor but take a peek at those Microchip 23A1024
SPI is not so slow after all. Put that with a Pic ( or other microCONTROLLER) with DMA channels ( microchip has even few 18F with them .... let see something like PIC18F44J11 ) and you can have something that might work

There are plenty of higher-end PIC's now which could do it, some have appreciable quantities of RAM, but the reasons for wanting to do it have long since passed - use an SD card instead.

However, back to the OP's original reason - why not just use a PICKit2/3, you can store the required program in the PICKit, and simply plug it in the target board to update the device. It's considerably smaller and lighter than a floppy drive, and doesn't require any complex programming in the target device.

 

[bryan1]

Why doesn't your PC run on a PIC if that's the case

Sworry Nigel just had to put this one in...... I've got a Duinomite running in my car as a standalone computer with a 7" lcd, connector for a PS2 keyboard, GPS connected and all running off a pic. Future plans are for a wii-nunchuck for a control device to cycle screens too. It does have an SDCard for logging but no ol' floppy but eh it is a computer running off a pic.....

At the moment it is only monochrome but soon I'll be doing the upgrade to full colour.

It is interesting too to see the speed difference between the gps output on the lcd screen for speed compared to my tomtom too as the 2 devices never agree but I take the NEMA data as the correct speed everytime.

Also now my Daughters have seen the LCD in the car they are now asking for a rear mounted lcd so they can play games in the back, well space invaders and pacman anyway.....

Cheers Bryan

 

[Nigel Goodwin]

Sworry Nigel just had to put this one in...... I've got a Duinomite running in my car as a standalone computer with a 7" lcd, connector for a PS2 keyboard, GPS connected and all running off a pic.

Like I said above, no problem with a modern high-end PIC - where you have large amounts of RAM.

However, a PC it isn't

 

[dougy83]

Nice backflip

 

[bryan1]

Like I said above, no problem with a modern high-end PIC - where you have large amounts of RAM.

However, a PC it isn't

Nigel it is a PC mate as it is a standalone unit capable of running programs and writing new programs WITHOUT the need of a modern PC. OK it is running Basic so just think of the Maximite/Duinomite as an old TRS-80 etc but running on steroids.

I am waiting on the release of the Olimex A10 board to come to Oz to replace my duinomite which will be running Debain linux as the OS too......

OK yea high end pic chips can and have been done as standalone PC's and the A10 board is off topic but eh I reckon it will give that friut board a good run for it's money too. Not for school kids but for industrial use the first boards are already being used....

Cheers Bryan

 

[Nigel Goodwin]

Nigel it is a PC mate as it is a standalone unit capable of running programs and writing new programs WITHOUT the need of a modern PC.

It really depends on your 'understanding' of PC, technically it just stands for Personal Computer, the first of which was probably the Commodore PET? - but in recent decades it's applied more to IBM compatibles than anything else.

I've also got a Maximite, incredibly impressive for almost nothing on the board - but that's the power of a 32 series PIC

 

[Nigel Goodwin]

Nice backflip

Not really, the main restrictions are the lack of RAM - some of the modern high-end devices overcome that - but it doesn't apply to this thread, which wasn't about such high-end devices.