Excellent Peter, definitely the way to go, a very neat solution. Just
out of interest what was the problem with plugging in the original drive
LED's.
Malcolm
On 14/12/2011 15:12, Peter Graf wrote:
Hi folks,
it's been a while... some might remember that I postponed my other QL
projects in order to design a "microdrive style" SD card interface for
the original QL.
I sometimes regret this decision, because the cost of time became
immense. I based my driver software on the QL-HD driver from Dirk
Steinkopf, which was originally made for XT harddisks. I liked his
concept of a C language interface. But unfortunately the sourcecode for
his stable releases was lost. So all I had were incomplete sources in an
experimental state. I got the driver to work with SDHC cards by now, but
fixes are still necessary.
On the more positive software side: I wrote QL-native-side FAT32 image
support for SDHC cards, which works well so far. This allows the same
removable medium to be used directly in both native QL hardware and PC
emulators. A feature which was only possible with floppy disks yet.
Please note that QL files are not places directly into the FAT32 system,
but into a container, a "block device image" file. This approach is
similar to QXL.WIN, but allows easier interfacing for native drivers.
The QL-SD hardware system has two parts:
1) A board which plugs into an internal QL ROM socket. It has a Minerva
style EPROM socket on top. EPROMs with QL operating system plus QL-SD
driver could be used here.
2) A board which is mounted behind a microdive slot inside the original
QL case. After the microdrive has been removed (which is quite simple)
the new SDHC-card drive can be mounted with two screws. SDHC cards can
be inserted just like microdrives :-) The drive LED for the SDHC card is
separate from the original microdrive LED, so no internal wiring must be
changed. It is visible beside the card socket.
Both parts are connected by simple a ribbon cable.
I finished the printed circuit board redesign yesterday and ordered more
prototyping boards.
All the best
Peter
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