Difference between revisions of "Disc Wizard"
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* It is restricted to loading/saving using DATA format disc. It uses sectors &c1-&c8 and reads/writes this entire range on each track in a multi-sector operation. DATA format has 512 bytes per sector, so sectors &c1-&c8 is 4K. So it reads 4K from each track. | * It is restricted to loading/saving using DATA format disc. It uses sectors &c1-&c8 and reads/writes this entire range on each track in a multi-sector operation. DATA format has 512 bytes per sector, so sectors &c1-&c8 is 4K. So it reads 4K from each track. | ||
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| + | * Disc must be pre-formatted to DATA. | ||
| + | |||
| + | * You can't use it with a disc with existing files because it writes data at specific places on the disc. It does write a dummy directory to indicate it's files are on there, but the device has the loader code in it, so you must use the device (or a seperate program) to load them back. | ||
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| + | * Track 1 is used for temporary storage (it saves the screen here and reloads it after). | ||
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| + | * It doesn't use the memory paging registers, so saves the RAM in it's current configuration. It saves the entire 64k starting at track 5 (for "1"). | ||
| + | |||
| + | * It writes a dummy directory to track 0. | ||
| + | |||
| + | * it writes 2 to f0e0 to disable it's own ROM and 3 to f0e0 to enable it's own ROM. | ||
| + | |||
Revision as of 08:56, 14 August 2013
The Disc Wizard was an addon from Draysoft & Evesham Micro Centre that allowed you to make dumps of the CPC memory to external storage, pretty much like the Multiface and similar interfaces.
Contents
Technical
- Button triggers NMI
- 8K ROM data has 4 regions. There is an NMI vector at offsets &0066, &0866, &1066 and &1866 within the ROM data. This suggests each of the 4 regions is selectable and mappable into the range &0000-&7ff.
What is not clear is that when the chosen region is mapped into the Z80 memory space if the region in &0000-&7ff is repeated through to the end of &3fff.
* Region 0 appears to be for saving "DraySoftONE". * Region 1 appears to be for loading "DraySoftONE" * Region 2 appears to be saving for "DraysoftTWO". * Region 3 appears to be for loading "DraysoftTWO"
It seems that the "1/2" switch on the PCB chooses between which 4k (assumption it is connected to A12 of the EPROM), then the "load/save" switch chooses between the 2k within that 4k (assumption it is connected to A11 of the EPROM).
- Dissassembly of the code indicates it uses direct FDC disc access for loading/saving.
- Dissassembly of the code indicates it uses an I/O port &f0e0, and sends the data 0,1,2 or 3. It is not clear the function or the exact decoding of this port.
- It is restricted to loading/saving using DATA format disc. It uses sectors &c1-&c8 and reads/writes this entire range on each track in a multi-sector operation. DATA format has 512 bytes per sector, so sectors &c1-&c8 is 4K. So it reads 4K from each track.
- Disc must be pre-formatted to DATA.
- You can't use it with a disc with existing files because it writes data at specific places on the disc. It does write a dummy directory to indicate it's files are on there, but the device has the loader code in it, so you must use the device (or a seperate program) to load them back.
- Track 1 is used for temporary storage (it saves the screen here and reloads it after).
- It doesn't use the memory paging registers, so saves the RAM in it's current configuration. It saves the entire 64k starting at track 5 (for "1").
- It writes a dummy directory to track 0.
- it writes 2 to f0e0 to disable it's own ROM and 3 to f0e0 to enable it's own ROM.
Unanswered questions:
- What happens when a reset is triggered?
- What is the decoding of the I/O port?
- Can the ROM be paged in and read through software?
- Can you have other files on the disc at the same time or is it a special disc format?
Pictures
- Draysoft & Evesham Micro Centre Disc Wizard
Front View
Back View
PCB Top
PCB_Bottom
- better pics by Terje Grind
Front View
Back View
PCB Top
PCB_Bottom
Manual
Download
- DiscWizard v1.2 zipped ROM file (ROM image for Emulators)
Links
- Disc Wizard at the English-language Wikipedia (Disc Wizard is mentioned in the Multiface's Similar products section)
