Pi1541

[jjh76]

For anyone who hasn't seen it yet, Steve White has released his Raspberry Pi 1541 emulator:

 

https://cbm-pi1541.firebaseapp.com/

http://www.lemon64.com/forum/viewtopic.php?t=67978&postdays=0&postorder=asc&start=0

 

[davidbrit2]

I've got parts arriving in the mail tomorrow. Looks like it'll be a simple build; I'm just going to make a hat out of perf board and some 2x20 header, then scavenge the 6-pin serial connector from the X1541 cable I built but could never get to work, and wire that directly to the 5V side of the level shifter. And if all goes as planned, I'll be playing C64 and Vic-20 games all weekend.

[awhite2600]

As an old C64 guy I feel silly asking this question, but it's been bugging me ever since I read about Pi1541.

 

I know that there are NTSC and PAL C64s with slightly different clock speeds and timing. Are there different variations of the 1541 to match the timing of the C64? If so, does Pi1541 support both?

 

I remember some fastloaders and copy protections were region specific, but this may be related to timing on the C64 side rather than the 1541 side.

[+OLD CS1]

Made one of the tech rags, too.

 

https://www.theregister.co.uk/2018/05/09/commodore_64_owners_rejoice_the_1541_is_back/

 

Very cool project.

[+SpiceWare]

That's really slick!

 

Any idea if it can emulate multiple drives? As in:

• device 8 = bbs.d64
• device 9 = forums.d64
• device 10 = downloads.d64
• device 11 = onlinegames.d64

[awhite2600]

 

That's really slick!

 

Any idea if it can emulate multiple drives? As in:

• device 8 = bbs.d64
• device 9 = forums.d64
• device 10 = downloads.d64
• device 11 = onlinegames.d64

 

 

There's a config file on the SD card that lets you select the device number. You can also select different ROM files (ie Jiffy DOS).

 

I doubt that it can emulate more than one drive. The author has stated that it was tough getting the timing to work for a single drive. He had to use bare metal programming (no Linux) to keep the timing tight enough.

 

I guess you could use multiple Pis to emulate more than one drive.

[davidbrit2]

 

That's really slick!

 

Any idea if it can emulate multiple drives? As in:

• device 8 = bbs.d64
• device 9 = forums.d64
• device 10 = downloads.d64
• device 11 = onlinegames.d64

 

 

I don't think it does currently, but the head-room should be there. It sounds like only 2 of the 4 cores are currently being used (one for USB/front-end handling, one for the drive emulation), so it might be able to handle another drive. Worst-case scenario, it could probably be made to only run whichever drive is currently active (so no independent disk-to-disk copy routines).

 

However, if you're just after a large "disk" for storing files without any fastloader tricks, then leaving out real 1541 emulation and simply using the communication protocols to store files directly on the SD card would probably be a better approach. Can't wait until it gets open-sourced and improvements and new features can start trickling in.

[+SpiceWare]

I figured multiple Pi1541s would work, the cable would need male and female connectors for the daisy chaining. Was just curious if multiple drive was something they'd thought of/looked into. Reading this it might be possible to emulate 2 or even 3 drives, but probably not 4.

 

 

Are there enough CPU cycles left in the RaspberryPi to have this handle something like modem emulation using some of the open GPIO and TCPSER?
This device could be double-duty.

It could be possible but it would have to be done with bare metal code.
I do have 2 and a half cores doing nothing.

For the core running the emulator timing is very tight....

 

[carlsson]

@AWhite2600:

I have never heard about floppy drives depending on a particular video region or even frequency on the input AC, in the case the drive even gets to taste the AC before it is converted to DC by the power supply.

[7800fan]

AFAIK the only time 50 vs 60 mattered is the video chip. I am pretty sure the serial port ran at the same timing since none of the disk drive depended on mains frequency at all. (1541-II and 1581 had separate power supply bricks that provided only DC to the drives)

[carlsson]

Cassettes can differ a little in pulses too, like +/- 0.02 MHz.

[davidbrit2]

I wired mine up tonight and it works beautifully. I played an assortment of C64 and Vic-20 stuff, and it was all flawless. I'm hoping it gets native .T64 support, because a LOT of games are archived that way, and it's a little tedious having to use something like DirMaster to extract the files. But it will load bare .PRG files right from the SD card, so you often don't have to worry about making a new disk image to hold the extracted files. Any C64 fans that are handy with a soldering iron have no reason not to do this. Well, unless you've already got a 1541 Ultimate or something.

[White Flame]

AFAIK the only time 50 vs 60 mattered is the video chip.

 

and the Time of Day clocks in the CIA chips, but pretty much nothing uses those.

[+SpiceWare]

the cable would need male and female connectors for the daisy chaining.

Never heard a daughterboard called a "hat" before, but this is a slick idea - Pi1541-Raspberry-Pi-Hat.

[jjh76]

Be careful if using more than one device. They're re-designing the circuit for the cable connector because although the original version will work fine if you're just using the Pi, if you daisy-chain other iec devices it can overload Pi's io pins

[davidbrit2]

Never heard a daughterboard called a "hat" before, but this is a slick idea - Pi1541-Raspberry-Pi-Hat.

 

It's pretty common terminology in Pi-land. The Arduino set call them "shields".

 

Be careful if using more than one device. They're re-designing the circuit for the cable connector because although the original version will work fine if you're just using the Pi, if you daisy-chain other iec devices it can overload Pi's io pins

 

Yeah, DON'T daisy-chain this thing with multiple serial devices if you built the original level-shifter interface design. You might be able to get away with one floppy drive without killing the Pi's GPIO. I haven't had any problems using it as the sole connected device, though.

[+OLD CS1]

 

and the Time of Day clocks in the CIA chips, but pretty much nothing uses those.

 

That was a good thing, actually. Since Commodore neglected them in the OS, instead using the jiffy-clock, that left two of them available, with alarm, available. I am pretty certain several BBS programs used the TOD, as I did in my own and several other utility programs. Though not relevant to the 1541.

[motrucker]

Finally, an affordable true 1541 emulator that's rather easy to assemble. What a great piece of hardware!

 

 

 

 

[davidbrit2]

Finally, an affordable true 1541 emulator that's rather easy to assemble. What a great piece of hardware!

 

 

 

 

Yeah, it's fantastic! I've been playing all kinds of stuff on my C64 and Vic-20, and all of it works great. Well, except for the mountain of C64 stuff that doesn't run right on an NTSC machine, and it'll be a few days before my 32K RAM expansion for the Vic-20 gets here, so I'm limited to 16K games at the moment. But so far I haven't really found anything that seemed like it failed on account of the Pi-1541. The only downside is that it perfectly emulates the slow loading speeds of a real 1541.

[+remowilliams]

This looks amazing. I have multiple 1541U's and I still want to try this...

[motrucker]

Yeah, it's fantastic! I've been playing all kinds of stuff on my C64 and Vic-20, and all of it works great. Well, except for the mountain of C64 stuff that doesn't run right on an NTSC machine, and it'll be a few days before my 32K RAM expansion for the Vic-20 gets here, so I'm limited to 16K games at the moment. But so far I haven't really found anything that seemed like it failed on account of the Pi-1541. The only downside is that it perfectly emulates the slow loading speeds of a real 1541.

I just got my setup running. It really does work quite well. Since I have NTSC machines, I have no problems. The loading times are true 1541 - I am about to see just how well the old fast loaders work. Not a bad deal; if you figure in the original prices it comes to about $35.00 USD.

I can't thank Steve White enough.

Edited May 31, 2018 by motrucker

[polyex]

Never heard a daughterboard called a "hat" before, but this is a slick idea - Pi1541-Raspberry-Pi-Hat.

Its a millennial thing. Daughterboard assumes gender.

[carlsson]

So motherboards now are mainboards?

 

(Last year I had to explain to a female retrogamer the difference between a male and female connector. She honestly didn't realize that the one with a pin is called male, and the one with a hole is called female.)

[+OLD CS1]

So motherboards now are mainboards?

 

(Last year I had to explain to a female retrogamer the difference between a male and female connector. She honestly didn't realize that the one with a pin is called male, and the one with a hole is called female.)

 

Watch yourself, mate... that could get you dragged in front of a tribunal!

[motrucker]

So motherboards now are mainboards?

 

(Last year I had to explain to a female retrogamer the difference between a male and female connector. She honestly didn't realize that the one with a pin is called male, and the one with a hole is called female.)

I can remember giving a talk at our old user group about connectors, then we noticed two women turning bright red. It was truly hard not to laugh, but......