Raspberry PI as a real Amiga Floppy Drive

[Solo761]

Originally Posted by Akira

I would recommend getting a model A just for this. it's cheap anyway!

I might even do that. But in that case I still wouldn't have an idea what to do with model B i have .

Originally Posted by Jeff_HxC2001

I made the RPi rev B working in full operation (linux+ethernet+usb) on the 5V line of the Atari ST without apparent problem. ( [ Show youtube player ] ). The other possibility is to use a DCDC converter on the 12V power line to make the RPi 5V. This will limit the current to ~400mA on the 12V.

I'm not familiar with Atari computers, is it off FDD power header or some other 5V source on the motherboard?
According to specs model B can pull 700mA (3.5W) and Amiga FDD power connector can supply 550mA (at least that's what the author says).

alternative to FDD connector is to have USB cable plugged into RPi and use external power adaptor (of course, it should be connected on same extension cord to have same zero line) or to use one of FDD conectors on ATX PSU that I already use as Amiga PSU .

Then again, I think it should work without problems even directly on motherboard. I just did little test with cheap power meter. I plugged in wall adapter and then RPi, maximum wattage displayed was 2.5W, most of the time it stayed on 2W. I think I have raspbian on SD card with default speed. But I doubt 100MHz overclock would increase power consumption by 2.5W (if I read it correctly, Amiga drive RPi files have config.txt which says that ARM frequency should be 800MHz, 700 is standard on RPi).

Originally Posted by kipper2k

just put an ohm meter in series with the Pi and measure the amperage going through. With just the Pi being used as a slave so to speak i can't see it requiring more than 500ma

I'll have to make some kind of power cable first. So far I only had USB ones which are not that easy to get ohm meter in series .
But also, I don't see it using more than FDD power header can give. Sure, B one has more parts than A variant, but they (ethernet, USB hub) aren't used in this application so they'll probably be in some kind of power save mode, and also I doubt GPU has much to do.

I'll try putting required files to SD and then see what my power meter shows, more or less it showed with raspbian booting.

[pandy71]

Originally Posted by lukassid

I wonder if raspberry could be an accelerator?

No without additional hardware and probably yes if some glue logic will be placed between ARM and MC68000 bus.
But it still can be used ac coprocessor (it can emulate 68882/40/60 - only particular library is required).

Nowadays 32bit uC with 50 - 150MIPS are easily available even in less than 48 pin packages... (ARM family AFAIR 8pin, PIC32 family 28pin)

But is must be clear that software (MC68K) transparent method require additional HW glue logic.

[lukassid]

Yes that might be difficult. What about Raspberry as a graphic card for the classic Amiga that little thing got HDMI! There is so many cool things on that tiny and cheap computer. I'm getting one now, I got HxC but I want to try Aros and RiscOs.

[Solo761]

Hmm, that would be funny. RPi flickerfixer .

[gulliver]

Originally Posted by lukassid

What about Raspberry as a graphic card for the classic Amiga that little thing got HDMI!

I did it like a year ago, just as a proof of concept (now I no longer have a raspberry). It is just a hack, but it works:

Use a VNC server in your Amiga
Configure an autologin raspberry
Use a VNC client in the raspberry
Connect both using ethernet (you can use serial ports but it would be awesomely slow).

Alternatively you can use an Xserver on the Amiga
and an Xclient on the raspberry.

Remember to enable compression if available, for better performance.

[kriz]

Very cool stuff this. But what about playing video files, would it be possible to send it to the RPI and let it take over the screen, files could be located on that or network stream, just to be able start it from the amiga and quit clean afterwards ... ahh would be so cool

[gulliver]

Originally Posted by kriz

Very cool stuff this. But what about playing video files, would it be possible to send it to the RPI and let it take over the screen, files could be located on that or network stream, just to be able start it from the amiga and quit clean afterwards ... ahh would be so cool

You can acomplish this in many ways using a network (with serial, ethernet or other):

1.use a video switch for your Amiga and raspberry. Normally the Amiga displays video, but when you trigger some raspberry app, you make it send a command to the video switcher so that the pi takes over the screen.

2.Use a vlab in your amiga and plug the raspberry´s output to it.

3.Make both machines client and servers with the programs I have already mentioned

4.Other solution you may think of. It all goes down to establishing a network between the Amiga and the raspberry and the finding a suitable protocol/api that you feel comfortable with.

[mram]

Hello,
thanks all of you, sorry for delayed answer, some vacation , some problem with emails and account

I'm happy most of you (except Jeff, it is complaining this interface in all blogosphere, this happens when you touch the business of people ) liked the solution.

I'm going to buy an ACA-500, which sounds really nice, do you recommend it to me? Is there any optimization I could do in the Amiga RPI Drive interface in order to take advantage of this new hardware?

[kipper2k]

Originally Posted by mram

Hello,
thanks all of you, sorry for delayed answer, some vacation , some problem with emails and account

I'm happy most of you (except Jeff, it is complaining this interface in all blogosphere, this happens when you touch the business of people ) liked the solution.

I'm going to buy an ACA-500, which sounds really nice, do you recommend it to me? Is there any optimization I could do in the Amiga RPI Drive interface in order to take advantage of this new hardware?

I actually bought one myself, mainly because i created a PC formatted CF card in it with all my ADFs on it. It is a handy way to both copy ADF's to disk and also create them. Fastmem is only 2mb so if using WHDload games the preload option is out of the question.. If you have the A500+ them 2mb of chipmem is the way to go.

Are you going to do more work with the Pi for the Amiga to improve it in any way. IPF support would be great, in fact the holy grail for Amiga floppies.

[mram]

Originally Posted by kipper2k

I actually bought one myself, mainly because i created a PC formatted CF card in it with all my ADFs on it. It is a handy way to both copy ADF's to disk and also create them. Fastmem is only 2mb so if using WHDload games the preload option is out of the question.. If you have the A500+ them 2mb of chipmem is the way to go.

Are you going to do more work with the Pi for the Amiga to improve it in any way. IPF support would be great, in fact the holy grail for Amiga floppies.

While the interface is able to rip a disk with XCopy (or another copying program) directly in adf files without any other operations, in case of no-standard disk it just make a raw MFM file, so depending on disks, this could be enough. Right now I don't have any protected disk to check this functionality.
The project just started and while Raspberry PI is cheap it is also powerful, so a lot of improvements can be made, in user interface and in functionality. I'm checking how many people are interested in it and what it will be the next step.
Lot of people is asking for external display, and I'm working on it, using a little color graphic display (3,5" 640x480 15 euro!) or the external video (usually Amiga is connected to SCART-RGB so in modern TV the CVBS input and HDMI input are available for Raspberry PI). For IPF I don't know how many disks need to use it, nowadays cracked ADF (with cool options) are available also for protected disks.
So you know, Rome wasn't built in a day

[Fingerlickin_B]

This is a very cool project!

Just a word on power & the RPi...

Note that while the RPi might "work" on 500-750mA, it tends to want to draw a lot more & running it on a low amperage PSU/power source may end up damaging it.

Mram's software may not be super power-hungry like a desktop OS, however it should be noted (just for example) that RaspBMC gets buggy if supplied anything less than 2000mA. The same is true of Rasbian & RiscOS.

When the RPi crashes due to low power, it also generally corrupts your SD card & you don't want that.

As the RPi will only draw the amps it needs, I feel a safe option is to give it 3000mA to chew on & then it'll get all it wants.

Again, really cool project mrarm! Just trying to help with the power business.

PZ.

[mram]

Originally Posted by Fingerlickin_B

This is a very cool project!

Just a word on power & the RPi...

Note that while the RPi might "work" on 500-750mA, it tends to want to draw a lot more & running it on a low amperage PSU/power source may end up damaging it.

Mram's software may not be super power-hungry like a desktop OS, however it should be noted (just for example) that RaspBMC gets buggy if supplied anything less than 2000mA. The same is true of Rasbian & RiscOS.

When the RPi crashes due to low power, it also generally corrupts your SD card & you don't want that.

As the RPi will only draw the amps it needs, I feel a safe option is to give it 3000mA to chew on & then it'll get all it wants.

Again, really cool project mrarm! Just trying to help with the power business.

PZ.

Yes, totally correct. You can use only the emulator software on the raspberry pi when connected to amiga, it doesn't use usb, ethernet, gpu so it is safe to be used powered from the Amiga. If you want to use as XBMC you have to disconnect from the Amiga powering it from another source, even if you use model A.

What I've done to make it is use a cable to raspberry pi a little bit longer so the connector come out 3-4 cm maximum, so I can attach raspberry pi outside the case when needed... (or sometimes I just don't close the case with screws,so I lift the upper part and place the RPI... )

@Fingerlick_B: Thank you, you're welcome

[Fingerlickin_B]

What amperage do you get from the 12V line on a standard A500 PSU?

PZ.

[mram]

Originally Posted by Fingerlickin_B

What amperage do you get from the 12V line on a standard A500 PSU?

PZ.

12V it isn't used (yet), only 5V...

[Fingerlickin_B]

I was thinking as someone else suggested, that maybe a stepdown transformer could be used if the 12V line provides enough amps?

PZ.

[mram]

Perhaps it is needed for future implementations.I don't know exactly, while 12V on PSU should give 0.5 A which is good, 12V on floppy connector by specification can give maximum 160ma... perhaps without using serial ports we can get more, to be checked on schematics, but with 160ma not so much improvement.
The most power will be required by USB and by LAN (which is the difference between model A and model B) but I think when we'll use it, it will be better to use the external floppy connector (which has more or less the same signals), and when we have an external usb cable and/or ethernet cable, have the power cable too (or through usb) should be not a problem.

All it depends on what will be next steps... ???

I'm thinking about external display (or to same tv) through video or hdmi to make easier the choice of the disks when we load more then 4 disks, and finally it is a minor change and only in software (if I can perhaps I can release this week). What you think?

[Fingerlickin_B]

Hey, the extra display thing is a great idea!

This gives heaps of options, not just with TVs, but with a lot of PC monitors.

If you had even a crappy monitor with VGA & digital inputs, users with Indivision (& other) scandoublers could just select the new input source when fiddling with disk images. Same would apply for TVs

As for the power, I still have no idea (maybe I didn't read the whole thread fully), but if 160mA is enough to power the RPi running your software, that's also great! If not, an extra PSU (or even modified PC PSU for everything) is a cheap fix
PZ.

[kipper2k]

The 12v supplied by the Amigas can be tapped into quite easily from the floppy connector on the motherboard and then regulated down to 5v. it may be possible to take part of the circuit and supply it from this regulated suppply and also use the native 5v supply to try to split the load.

[seuden]

Love this thread! Great stuff!

[kipper2k]

work in progress





The board is a little smaller than an actual floppy drive and is designed so that the Pi can be mounted on it and installed in the Amiga. I added a slot so the A600 cable can be fed through it to allow for a shorter tidier cable. The Pi will connect via a small 26 pin IDE cable.

The design placement itself may change as i find errors etc. There's lots of room on the board for other enhancements.