Enterprise conversion of the CPC+ program Crazy Cars II The program runs on EP64 also, but in this case the map function can not be used.
Controls:
Hold: pause
Esc:  end game
M:     map
Q,A,O,P,Space/int/ext1/ext2 Joy

EXOS 2.4 beta 3
-don't freeze on real machine (previously the ep128emu not fully emulated the Z80 reset, then the problem not noticed on emulator)
-at reset the current frequency written to Dave port 191
-memory wait states disabled at default (can be enabled with SET 191,4 commands)

Updated ep128emu EXE
-Z80 reset emulation enhanced
-254 tracks floppy images now supported (on real machine it can be used with HxC floppy emulator)
-Fixed the bug in 2.0.9.1 version: in debugger memory dump the ascii characters printed in reverse order.
-Fixed the bug in 2.0.9.1 version: in CPC emulator mode the floppy leds not always shown

I try to make a fast as possible Enterprise:
Previously 6 and 7.12 MHz turbo modes existed. About 20 years ago I tried 8Mhz but it is unstable. At that time I had only Z80B CPU.

Now I have new Z84C0010PEG CPUs, and standalone crystal oscillators (instead replacing the crystal in the motherboard clock generator circuit).
Firstly tried again the 8Mhz: working!

Ok, lets try the 10Mhz: working!!!
It looks stable, tested for an hour on two different motherboards, one with the old 08-04 Nick, and one with the new 08-47.
Only very few modifications were needed to reach this speed:
-original 8Mhz System Clock generator circuit replaced with 20Mhz crystal oscillator
-Z80A replaced with 10Mhz Z80
-R12 short circuited
-100ns EPROM used for EXOS
Video memory access controled by Nick fixed timing, then no problem. Other RAM/ROM needed to be replaced with faster ones, but today very fast SRAM and Flash ROM chips are available.

Ok lets try something better
Put a Z180 CPU into the Enterprise! In the old times news about the next Enterprise model developed with Hitachi Super Z80 (Zilog later licensed back, and named to Z180), unfortunately this machine never released.
Now I try to build this configuration.
On same clock speed, the Z180 20-30% faster than the Z80.

There is the wiring diagram, and photo of the prototype
It is a surprise but working
Current beta version of EXOS 2.4 now can identify and initialise the Z180.

It is a problem, because the Z180 divide by 2 the external clock signal for the CPU core. The stretched CPU clock from the Nick mess up the Z180 CPU core clock generation, then the video accessing is too slow
Now I try to build Wait signal genarator for the video access, then Z180 use the System Clock, and waited by the Wait signal.

And what is the best case scenario ? What speed do you hope to reach ?

I hope 10 Mhz Z180 which is more than 3x faster than the original 4 Mhz Z80.

I hope 10 Mhz Z180 which is more than 3x faster than the original 4 Mhz Z80.

Not bad, but the emulator can show programs with extreme "overclocking", and the 3X multiplier is not worth the work maybe, is it ?

And the 6Mhz z80 almost killed the click sound, this machine will kill it, definetly.

Is the click sound the only one speed sensitive/critical part of the exos/exdos ?

This would be an interesting thing, when the cpu clock can be raise to 20,40 or more MHz ... it can be work like an Amiga, or something ... With 100% compatibility, of course.

Don't you think this ?

By the way Z180, according to some quick search in google, eg wikipedia article mentiones SPI (and DMA, UART etc) as a built-in feature of some models. That's interesting as having a hardware SPI implementation means easy interfacing (no "glue" MCU needed!) with SPI capable devices, like SD cards in general (but there are many, including eg SPI based FPU with many interesting feature: Micromega's um-FPU, ethernet controllers, memories, RTC, etc, some of them are more common with the slower I2C bus though)...

Enterprise 128 conversion of Amstrad CPC game Gun Fright. The game is EXOS compatible, and runs on EP64 also, however soft reset does not work on EP64, because system segment is used for Video Memory, and littlebit slower than on CPC, the game is littlebit faster on EP128 than on CPC, because the game has been modified, and uses 2 screen for graphics, on CPC there 1 active screen, and a background where the game screen were written, and later it is copied to the active screen.
There is a small bug, which was came by the modification of using 2 active screens for Graphics, on the left side of the screen at the 3. character column sometimes sprite pixels appear, I copy only 4 character from the border, 6, or 7 should be, but I left in this way, I did not want to decrease the speed.
Controls:
QAOP space
INT JOY+ENTER
EXT1/2 JOY

Keys in game:
ESC - Pause
F8 - change palette of game

Palette mode Keys:
F7 - Exit from palette mode
F1-F4 - change color0-color3
INT JOY - move on the palette
ENTER - reset colors to original