WIP: internal 512K expansion

[eto]

Ah. did you use the second DATA Application disk?

I switched to the first disk in AMsdos, then I start SymbOS - and then I can't "insert" the application disk. I only have the M4 and no disk drive. 

Try my Big dsk too. I wonder if the M4 will chew it up.

doesn't work. M4 shows dozens of 0KB files without any name.

[McArti0]

check out something more typical. 720kB

[prevtenet]

I believe it's more common to run SymbOS from mass storage on the M4, rather that using a disk image. The SymbOS CPC download package has a .ZIP file with a complete installation you can extract to the M4's SD card.

[HAL6128]

Ah. did you use the second DATA Application disk?

I switched to the first disk in AMsdos, then I start SymbOS - and then I can't "insert" the application disk. I only have the M4 and no disk drive.

Try my Big dsk too. I wonder if the M4 will chew it up.

doesn't work. M4 shows dozens of 0KB files without any name.

There's a SymbOS for mass storage (M4) prepared where you don't need a floppy. It must be in the download container in the SymbOS website.

[eto]

Okay, I try this. Wasn't obvious to me that this is for M4 too. But hey, I never used the M4 before.

check out something more typical. 720kB

thanks, I'll give it a try.

[Prodatron]

@Prodatron What's the best solution to run SymbOS from M4? I could mount a DSK but then I could not figure out how to start a program - I only get the error that no program can be found.

Just download this:

http://www.symbos.de/download.htm#marke0
http://www.symbos.de/download/20211230-V31/symbos-cpc.zip

There is "a complete installation for the M4Board" included, you only need to copy the files/directory of "SymbOS-CPC-MassStorage" to the root of your SD card and then...

RUN"SYM

that's it!

PS: Yes, I am a bit late, Prevtenet/HAL6128 were right!

[McArti0]

Ver 2.04 M4 "Fix DSK file size 0 bug"

Ps. If Duke didn't know about IBM disk support, M4 might not shot in the directory.

[eto]

There is "a complete installation for the M4Board" included, you only need to copy the files/directory of "SymbOS-CPC-MassStorage" to the root of your SD card and then...

RUN"SYM

that's it!

Thanks... I have put the contents into a subfolder - which didn't work but now I have moved it to the root folder and it worked.

Good and bad news:

• 6128 version perfectly works - and I could start plenty of apps 
• 464 version crashes after boot   

I need to check the logic for the RAM shadowing - or skip C3 mode for now.

Which software needs C3? I am only aware of Future OS. Any games that require it?

[Prodatron]

#C3 only makes sense for ROM software accessing the "VRAM" in read mode.
I guess 99,9% of any CPC software will work fine without #C3.
No disc-based games are using this, as it doesn't make any sense.
IIRC CP/M Plus may use it (without any reasons as you can have a very fast 63K TPA without this mode as well  ).

[ajcasado]

I need to check the logic for the RAM shadowing - or skip C3 mode for now.

Which software needs C3? I am only aware of Future OS. Any games that require it?

The FUZIX port uses C3 for accessing the video ram, but as it doesn't run code on ROM the shadowing is not needed. I run it on a 664 with the Z-MEM from TotO without problems,

[eto]

Getting closer...

The second version of the 6128 board technically works - however I have put the ICs too close together and need to give them a bit more space.

So... another 2 weeks ;-)



 

[SerErris]

Is the green cable just a botch wire to adjust for some errors, or is this a permanent thing to connect to the original mainbord?

[eto]

s the green cable just a botch wire to adjust for some errors, or is this a permanent thing to connect to the original mainbord?

A fix for a fix ;-) I was not sure if I had an error and had to cut a trace to try that out - just to recognize it was a mixup of pins in the PAL equations. So this cable fixes the "fix".

So still no wire required to plug this into the 6128.

[GUNHED]

@GUNHED how can I start FutureOs from M4 on a 464? It is installed in ROM 10 and above but ROM 10 doesn't get initialised on the 464.

Shall be easy... I hope...
- Get the new installer DSK from www.FutureOS.de (click left at downloads)
- Start the installer with run"disc
- Select as target device the M4 and CPC (not the Plus version)
- Do a hard-reset: Switch your CPC on and off (including M4 power supply)
- Start FutureOS using command |os

That's it. 

Comments:
- On CPC464 the first FutureOS ROM (A) needs a ROM number lower than 8. Or you can use the CPC6128 firmware+BASIC, then ROM A can have any ROM number (0-15). The other ROMs can have any number (1-255)
- There is a folder for the M4 SD-card (see downloads at www.FutureOS.de) which contains all stuff for FutureOS. Just put that folder in the rood directory of your M4 SD-card. Under FutureOS use the IDE / mass storage icon or hot key "a" to access the mass storage features.

[SerErris]

As Gunhead wrote, you just need to put the first ROM in slot 0-7.

If you have a disk controller 7 is used and 6 would be appropriate. CPC 464 does not initialize anything higher than 7. That is why you do not see anything if you assign it to rom number 10.

You could manually call the init routine - however, it is easier to put the first rom to anything the 464 sees by default.

[eto]

You could manually call the init routine - however, it is easier to put the first rom to anything the 464 sees by default.

I am aware of that but the FutureOs installation copies the ROM to #10 - and that doesn't work on the 464.

I didn't try the 6128 ROM yet. Maybe that will help. 

- Get the new installer DSK from www.FutureOS.de (click left at downloads)

I don't have a disk drive on the 464. 

[SerErris]

If you use the 6128 OS Rom in a 464, than it will work - remember to also put in the 6128 Basic as well (upper 0), otherwise it will crash.

[GUNHED]

You could manually call the init routine - however, it is easier to put the first rom to anything the 464 sees by default.

I am aware of that but the FutureOs installation copies the ROM to #10 - and that doesn't work on the 464.

I didn't try the 6128 ROM yet. Maybe that will help.

- Get the new installer DSK from www.FutureOS.de (click left at downloads)

I don't have a disk drive on the 464.

The installation of FutureOS allows you to select ROM-numbers of course! 

For a typical CPC464 with &C3-compatible RAM expansion, you would select a ROM number between 0 and 7 for ROM A. And for the other ROMs (B, C, D, M4) just take what you want.
If ROM A goes to ROM slot 0, then autostart after Reset is active. 

If you have only tape on CPC464 it makes no sense anyway, since FutureOS is working with discs/hard-discs. Or with floppy-emulators. (Or, from M4 SD-card, installers are in 'FutureOS' folder there too).

Sorry for getting off-topic, hope this can help a bit.

[eto]

Update: the latest PCBs were stuck in transit for almost 2 weeks - but they finally arrived and I could do some further tests and check if it's possible to use the internal 2nd RAM bank on top of the 512k SRAM - and indeed it seems to work. So it should be possible to upgrade a 6128 to 640K internally - still no soldering required.

Upgrade process will be simple:
1) take CPU out of the socket on the MB and put  it into the socket of the expansion board
2) put the expansion board into the CPU socket on the MB
3) optional: add a disable-switch to disable the RAM expansion from outside (black/red wire in last picture)

If disable via the switch the 6128 will behave exactly like if no RAM expansion was built in.

I have to make another revision of the board as I need to adapt some traces in order to make the 640K version work (green wires in last picture) and the space in the 6128 is so tight that I need to move the CPU 2mm up to make sure that there is no chance of collision with the keyboard.

I guess it will take another 4 weeks until the next update.

[eto]

one picture was missing...

[McArti0]

So you have a 64+512+64 organization where for A8=1 internal second 64kB works. Right?

[Prodatron]

Great news, thanks for sharing!
One of those cool projects that makes you wonder why no one has done it this way before.

[McArti0]

@eto do you have RAMDIS connected as OpenEmiter, i.e. only +5V with 2.5mA output and no GND?

[eto]

So you have a 64+512+64 organization where for A8=1 internal second 64kB works. Right?

A8 = 1 => SRAM  (&7f00)
A8 = 0 => internal second RAM (&7e00)

the other way around the SRAM would not be visible for software that only supports the usual 576K max.

@eto do you have RAMDIS connected as OpenEmiter, i.e. only +5V with 2.5mA output and no GND?

I originally tried with RAMDIS but that would have required soldering as RAMDIS is not available on the CPU socket. I'm now interrupting the MREQ signal to prevent the GateArray from creating the memory access signals when the SRAM is accessed.

[eto]

One of those cool projects that makes you wonder why no one has done it this way before.

That's exactly the question why I originally started it (and because I don't like the external RAM expansions).

But to be honest if I would have known how much work it is to figure everything out, I would not have started it.