New multi purpose board:512K RAM Expansion/32x Rom board/256K Ram+2X Rom board

[ikonsgr]

Frankly, i didn't expect such demand, 20boards left in first 2days... 
For the moment,i only have 3-4 boards left, and in a few weeks another 10 when i receive the sram chips.

[entelle42]

Hi, great job!! 1x unit for me. Email sent

[poulette73]

Frankly, i didn't expect such demand, 20boards left in first 2days... 
For the moment,i only have 3-4 boards left, and in a few weeks another 10 when i receive the sram chips.

Ready to break the USIfAC sales record ? 

[Prodatron]

Having enough RAM is always a good thing

[ikonsgr]

Ready to break the USIfAC sales record ? 

 For such short time, surely this is a record, i don't recall USIfAC II ever sold ~2 dozens boards in a few days 
Btw, USIfAC II is closing to 300 boards sold (in ~20 last months).

[GUNHED]

Does the 512 KB RAM part work with FutureOS too?

[ikonsgr]

Does the 512 KB RAM part work with FutureOS too?

Haven't tested, as FUTURE OS needs also a rom board. But i suppose someone who already bought the board might be able to try it, and tell us 

Btw, i currently have only one board left (i had a couple of bad sram chips ), and in a couple of weeks, another 10 boards will be available.

[ikonsgr]

And a small request:  Although i made extensive tests to ensure board works well, as this is a new project,  i would really appreciate any feedback for any bugs or incompatibilities with specific games/programs.
Also, it would be very interested to verify that the 512K ram mode, works with other hardware too, like M4 , DDI interfaces, ROM boards etc.

[d_kef]

Today I spent some time playing with my new board and here are my findings so far:

1) The combination of USIfAC II + 512K RAM Expansion/32x Rom board/256K Ram+2X Rom board (by the way @ikonsgr you need to find a shorter name ) is working as expected with my 6128. Both RAM and ROM expansion were tested.

2) The combination of M4 Board + 512K RAM Expansion/32x Rom board/256K Ram+2X Rom board is not working with my 6128.
The 6128 freezes immediately after showing the M4 initialization message. The M4 had no ROMS installed and it works flawlessly with another 512K RAM board using the same cable. I also tried to change the M4s ROM nr to no avail.

3) I can't test the combination of USIfAC II + 512K RAM Expansion/32x Rom board/256K Ram+2X Rom board with my 464 because my USIfAC II freezes. The 464 boots to the USIfACs ROM initialization message then reboots and freezes after showing the Amstrad FW message. I have an early model with the tall keys and a 40007 gate array.

4) The combination of M4 Board + 512K RAM Expansion/32x Rom board/256K Ram+2X Rom board is working with my 464 but C3 memory mode is not. So CP/M Plus is not loading and Future OS 8 boots but the mouse pointer leaves traces on the screen.
The strange thing is that when the selector is in 6128 position loading CP/M plus fills the screen with garbage as expected when C3 mode is not working but when the selector is in 464 position loading CP/M just clears the screen as if it was loading normally on a 6128 but CP/M never comes up. I tried with CP/M Plus .DSK file, Graduate CP/M Plus ROM, and HDCPM and all of them had the same behavior.
Furthermore with some .DSK files the directory (contents of .DSK) was not showing correctly and couldn't load the containing game. Other .DSK files worked just fine.

d_kef

[Richard_Lloyd]

Hello, my initial tests of the new board are as follows.

The board works fine when it is the only thing connected to my CPC6128.

On my CPC6128 the new board works fine with the following and is connected to the far end of the @revaldinho MX4 expansions.
@revaldinho  Eight ROM Card
@revaldinho CPC-CPLink RPi Co-processor card

The only problem card so far is the Dandanator. When that is connected, the computer does not boot up - I just get a screen with some colour bars. This is low priority as the Dandanator is mostly used on it's own with nothing else connected.

Hope that helps, more to follow.

Richard.

[ikonsgr]

2) The combination of M4 Board + 512K RAM Expansion/32x Rom board/256K Ram+2X Rom board is not working with my 6128.
The 6128 freezes immediately after showing the M4 initialization message. The M4 had no ROMS installed and it works flawlessly with another 512K RAM board using the same cable. I also tried to change the M4s ROM nr to no avail.

Hmmm, i suspect 2 possibilities, either M4 uses printer port (address bit Α12=0) on boot, (and it might  conflict with RAM/ROM board, which also uses printer port for communication), or ram/rom board might not be able to "pass through" the required power and/or other signals adequately, as M4 is quite more complex board than USIFAC II.
Now, i suppose you plugged M4 on ramrom board, right?
Did you use both 50pin connector and edge connectors?
Did you try to remove the internal supply jumper and use an external 5v psu?
Finally, if you have a MX4 board with multiple connectors, did you try to plug ram/rom and M4 board separately on MX4 board?

3) I can't test the combination of USIfAC II + 512K RAM Expansion/32x Rom board/256K Ram+2X Rom board with my 464 because my USIfAC II freezes. The 464 boots to the USIfACs ROM initialization message then reboots and freezes after showing the Amstrad FW message. I have an early model with the tall keys and a 40007 gate array.

Unfortunately, my cpc464 has a 40010 so i couldn't test it with 40007 to verify any possible incompatibility with it. It would be helpful if anyone else with a CPC464 and 40007 gatearray, can report problems too.
Anyway, to verify any board design problems with specific amstrad revision boards, did you use both 50pin connector and edge connectors? Also, did you try to remove the internal supply jumper and use an external 5v psu?  Btw, what board and fw version of USIFAC II you have?

4) The combination of M4 Board + 512K RAM Expansion/32x Rom board/256K Ram+2X Rom board is working with my 464 but C3 memory mode is not. So CP/M Plus is not loading and Future OS 8 boots but the mouse pointer leaves traces on the screen.
The strange thing is that when the selector is in 6128 position loading CP/M plus fills the screen with garbage as expected when C3 mode is not working but when the selector is in 464 position loading CP/M just clears the screen as if it was loading normally on a 6128 but CP/M never comes up. I tried with CP/M Plus .DSK file, Graduate CP/M Plus ROM, and HDCPM and all of them had the same behavior.
Furthermore with some .DSK files the directory (contents of .DSK) was not showing correctly and couldn't load the containing game. Other .DSK files worked just fine.
d_kef

When switch is set to "6128" position, board doesn't suppress MREQ signal, which is required on CPC464 for the expansion RAM to function. This suppression might cause problems with some game/utilities, especially with new OS like symbos or futureos (i verified this with symbos, although it works ok on a cpc6128 and setting switch  to "6128" position). Anyway,as using 
Amstrad diagnostics with my CPC464, reports support of C3 mode in both 512K RAM and 256K RAM/2x ROM modes  video, could you provide the dsk images you used for futureOS and cpm to test them with my CPC464?

[d_kef]

Now, i suppose you plugged M4 on ramrom board, right?
Did you use both 50pin connector and edge connectors?
Did you try to remove the internal supply jumper and use an external 5v psu?
Finally, if you have a MX4 board with multiple connectors, did you try to plug ram/rom and M4 board separately on MX4 board?

I tried:
1) with M4 on ramrom board
2) on a separate cable connected to the edge connector of ramrom board
3) on a cable with 2 female IDC connectors which should be similar to MX4
The behavior is exactly the same

Unfortunately, my cpc464 has a 40010 so i couldn't test it with 40007 to verify any possible incompatibility with it. It would be helpful if anyone else with a CPC464 and 40007 gatearray, can report problems too.
Anyway, to verify any board design problems with specific amstrad revision boards, did you use both 50pin connector and edge connectors? Also, did you try to remove the internal supply jumper and use an external 5v psu?  Btw, what board and fw version of USIFAC II you have?

I used the same cable / board combinations as with the 6128.
I didn't try with an external PSU but I use a an external regulated 5V/5A PSU which gives a nice and clean 5.2V output at all times. I also tried to power the system from with the CTM644 but there was no difference.
I'll try with an external PSU for the ramrom board and report back  (when I find some time to search my box of PSUs and find one with the correct DC characteristics and the correct plug type).
USIfAC II has been upgraded to 6f but I also tried with fw 6d.

When switch is set to "6128" position, board doesn't suppress MREQ signal, which is required on CPC464 for the expansion RAM to function. This suppression might cause problems with some game/utilities, especially with new OS like symbos or futureos (i verified this with symbos, although it works ok on a cpc6128 and setting switch  to "6128" position). Anyway,as using Amstrad diagnostics with my CPC464, reports support of C3 mode in both 512K RAM and 256K RAM/2x ROM modes  video, could you provide the dsk images you used for futureOS and cpm to test them with my CPC464?

I just made an important discovery. @llopis Diag ROM shows support of C3 mode even for my other ROAM board which I definitley know it is NOT supporting it (as I designed it). So I wouldn't count on the diags reliability on this matter.

d_kef

[ikonsgr]

Diag ROM shows support of C3 mode even for my other rom board which I definitley know it is NOT supporting it (as I designed it). So I wouldn't count on the diags reliability on this matter.
d_kef

 Thanks for the follow-up on testing. I might need to widen ground/common traces (as for 5v power supply too) on the board, this is how i fix such problems in the past.
Btw,can you suggest a tool (in file or dsk form) for checking C3 mode support then?

[d_kef]

Thanks for the follow-up on testing. I might need to widen ground/common traces (as for 5v power supply too) on the board, this is how i fix such problems in the past.
Btw,can you suggest a tool (in file or dsk form) for checking C3 mode support then?

Well I never needed one but as a general rule If CP/M Plus is booting to the command prompt then C3 mode is working.

d_kef

[ikonsgr]

Well I never needed one but as a general rule If CP/M Plus is booting to the command prompt then C3 mode is working.
d_kef

 Ok, photo is taken using CPC6128 with RAM/ROM board (512K Ram mode) and "464" mode (MREQ supress enabled). Does this means that C3 mode is indeed supported?

[d_kef]

Yes it is! But the 6128 supports it natively.
I thought the point was to give the same functionality to the 464.
Or am I missing something?

Edit:
Ok. I just re-read the board's instructions and it is clear that the selector suppresses the MREQ signal for better compatibility. That's not the same as supporting C3 mode. My bad 

d_kef

[ikonsgr]

Yes it is! But the 6128 supports it natively.
I thought the point was to give the same functionality to the 464.
Or am I missing something?

d_kef

Unfortunately cpm plus only runs using a real disk (i transfer the image to a floppy disk using |DSK command), when using dsk image and FDC emulation, it freezes at some point of loading (on either CPC464 or CPC6128, with or without RAM/ROM board). So i could only test it with a CPC 6128, but when RAM/ROM board is connected, the internal control of ram banking of cpc 6128 is deactivated, and ram/rom board takes over memory management. Is there any utility on cpm plus that can report or test all available memory?

[ikonsgr]

Edit:
Ok. I just re-read the board's instructions and it is clear that the selector suppresses the MREQ signal for better compatibility. That's not the same as supporting C3 mode. My bad 
d_kef

Actually the suppression of MREQ is mandatory on CPC 464 otherwise ram expansion will not function at all ("officially" cpc464 didn't support memory expansion, without MREQ suppression, every write to a ram expansion block address, writes to same address of internal ram too)!

[ikonsgr]

-

[d_kef]

Unfortunately cpm plus only runs using a real disk

Not really! You can always use HDCPM 

d_kef

[revaldinho]

@Duke created a short program which does a good job of testing the first 512k of expansion RAM and reporting the level of C3 compatibility.

The source is on Github.

There is also a binary attached to this older thread

[ikonsgr]

I just test board using duke's ramtest program. On CPC6128 everything works ok, but on CPC464, C3 mode is not supported because of the required internal ram remapping from block 1 to block 3, which practically means that when C3 mode is enabled, and A15=0 & A14=1 (address &4000-&7fff) then A15OUT=1 & A14OUT=1 (adress &C000-&FFFF).
Of course this requires for the A15 and A14 INPUT signals from CPU, to be seperated from the A15 and A14 OUTPUT signals that goes to RAM chips (through a 74LS1453 multiplexer).
On a CPC 6128, A15 and A14 address bits from CPU, are ideed directed to the HAL16L8 (that controls memory managment) which then gives appropriate A14OUT and A15OUT signals. And these signals are then drive the 74LS153 multiplexer, that controls internal RAM's A15 and A14 address bits:

You cannot view this attachment.

But,on CPC464, both A14 and A15 INPUT signals from CPU, goes DIRECTLY to 74LS153 multiplexer that controls internal RAM's A15 and A14 address bits:

You cannot view this attachment.

So, the only way to support C3 mode on a CPC464, might be using some latch circuit that "Catches" momentarily the A14 & A15 input signals, and then alters the same A15 signal...   Is there any RAM board that supports C3 mode on CPC464?

[revaldinho]

So, the only way to support C3 mode on a CPC464, might be using some latch circuit that "Catches" momentarily the A14 & A15 input signals, and then alters the same A15 signal...   Is there any RAM board that supports C3 mode on CPC464?

My Universal CPC RAM cards provide full support for C3 mode on the CPC464/664 and can run FutureOS and CPM+ without problem. There isn't a lot of other software which needs full 6128-like C3 mode support though.

The trick is to allocate one 64K bank of RAM to shadow the internal memory and then use that for reads rather than the actual base memory in C3 modes. Full documentation and all the code is shared under the GPL in the project Github site, and the cards have been discussed here including in the thread I linked with Duke's RAM test. You may be able to adapt the shadow memory mode to your new card although you can't get away from having to back-drive one of the memory address lines.

[d_kef]

Also the Dk'tronics RAM expansions offered support for C3 mode by overdriving /MREQ and A15.
Discussion here and here.

d_kef

[ikonsgr]

although you can't get away from having to back-drive one of the memory address lines.

Well, this "back drive" (of having A15 address bit '0' as input and output it to '1'at the same time...) is what puzzles me...
Maybe this is feesible using CPLD, but i don't think you can do it, using CLC's from the PIC mcu... 
Anyway, as you also mention, this C3 mode is practically used only with future OS and CPM+, so it doesn't affect the ability to run games and other programs that require 128k ram on cpc 464 (or need 6128 fw+basic too, using the dual mode of 256k ram+2x roms),which i suppose is the "main point" for most cpc464 owners