X-MEM

CPC X-MEM

Technical

ROMs are selected using the normal ROM selection I/O port (DFxx).

The CPC sees Roms the X-MEM at rom slots 0-15 and &40-&4f.

&40-&4f are always visible regardless of the ROM lock or ROM boot switches. If you wish to program the flash use the &40-&4f range.

When "boot from CPC" is activated, rom 0 and OS are not paged in by the X-MEM but can still be accessed at &40 etc.

The flash is mapped contiguously to roms 0-15 so that when programming the flash you need to translate the flash address from the documentation to an appropriate rom slot and address in the range &c000-&ffff.

e.g. for flash address &05555 use DF41 and address &D555. For &2aaa this is DF40 and address &EAAA.

TO BE CONFIRMED: Writing to the flash also writes to the RAM underneath the ROM? TO BE CONFIRMED: Writing to the flash requires upper ROM to be paged in?

X-MEM Floppy Disc Utilities

X-MEM Init Pass

This program allows to clear all the 32 ROMs stored inside your X-MEM board. RUN”INIT” The process takes one minute to erase all the slots. After that, your X-MEM will be not able to boot if you don’t install it first. Don’t forget to set the BOOT switch (2) to “CPC” position to continue.

X-MEM Install Pass

This program allows to install the X-MEM after the Init pass. Also, it can up- date the Firmware and BASIC, targeting your CPC and keyboard layout. RUN”INSTALL” The process takes few seconds for reprogramming the Lower ROM and ROM 0. Then you will be able to choose the CPC target model for programming the X-MEM. Notethat ROM 1 willbeusedinthefuturetoextendthe Firmware 3.14. Currently, a 448K RAM Drive“C”is installed. Use |C from BASIC or C: from CP/M.

X-MEM Rescue Pass

If your X-MEM is programmed with one (or more) defective ROM(s) that pre- vent your computer to boot properly, please turn it off. After that, set the READ ROM jumper (4) to “NO” and turn it on again. RUN”RESCUE”

In all these cases, make sure that your X-MEM ROM switch (3) is set to “FREE”. For software updates and support, please visit: http://www.centpourcent.net

Introduction

Thank you for choosing this new ACME hardware for your good old CPC! The X-MEM is the state of the art of the memory expansions. It embeds up to 512K RAM/ROM and allows to replace the Lower ROM and ROM 0 to use different Firmwares and BASIC to push all CPC at the same level of compatibility.

X-MEM Diagram

• 1. CPC 464/6128 switch = Set RAM mode for 464/664 or 6128
• 2. BOOT CPC/ROM switch = Set boot mode from CPC or X-MEM
• 3. ROM LOCK/FREE switch = Set ROM write protect, like a floppy tab
• 4. READ ROM NO/YES jumper = Ignore the ROM part. Rescue mode only!
• 5. Expansion port connector = To MotherX4 or CPC using a ribbon cable

Firmware 3.14

1. FW Boot

Display the real amount of RAM and the CRTC type of your computer. You can skip the ROMs initialization by keeping the ESC key pressed while (re)booting. It’s a safe way to run conflicting programs and avoids to apply a rescue pass.

2. ROMs Init

The Firmware 3.14 initializes the first 32 ROMs with RSX support on all CPCs. The ROMs messages are disabled to boot faster and not scroll the screen.

3. Burning ROMs

You can program from BASIC the X-MEM: CALL &B8DD,<source>,<rom_id> i.e. “CALL &B8DD,&4000,15” set the ROM 15 with 16K loaded at &4000.

FutureOS Lower ROM

The X-MEM provides the feature to replace the LowerROM (you can use the ROManager to install any kind of lower ROM with it). The LowerROM for FutureOS will work to autostart the OS.

Troubleshooting

Q1: After plugging properly the expansion, I get random bugs or no display. A1: Check the boot switch (2) position and clean your CPC Expansion port.

Q2: All programs don’t detect the extra RAM on my 464/664 and fail to run. A2: Check the RAM switch (1) position, then your +5V power supply.

Q3: My favorite utilities fail to program the X-MEM ROMs. (RMA, ROManager, ...) A3: Check the ROM switch (3) position. Use only the provided programs.

Q4: After programming some ROMs, my CPC gets sticked at FW initialization. A4: Try to boot with the ESC key pressed, then apply the X-MEM rescue pass.