Am 21.05.2011 14:23, schrieb Miguel Angel Rodriguez Jodar:
El 20/05/2011 19:37, Urs Koenig (QL) escribió:
@Miguel (Angel Rodriguez Jodar): Any news?
Hi! I've made some improvements to the SPI code, so it works very
reliable for all SD cards (not SD-HC) I've got at home. Currently I'm
studing the inners of QDOS and learning how to write a directory
device driver (I'm new to the QDOS/SMSQ world).
Using the Retro-X software ans dome custom C code, I've been able to
make longer "QL movies". Some days ago I copied a whole Big Bang
Theory episode into an SD card and replayed from my QL :)
In the meantime, I've received a batch of more than 50 small flash
EPROM chips (PLCC32). Half the size of a regular DIP EPROM, flash, not
UV, and 128K size. Being flash means that I can offer an option to let
the user burn a new firmware version. As they are 128K insize (eight
times the size I really need), I can have a "fail safe" option,
suitable for recover from broken firmware.
My roadmap is:
- To have a design that let me operate a SD/MMC card from the ROM port
(done!)
- To have a reliable and consistent set of low level routines for SPI
operations (done!)
- Write a small device driver (not a directory device driver) to train
myself. This device driver will use the SD card as a charactger device
(in progress).
- Continue learning about QDOS/SMSQ and directory device drivers (I
have the source code of QUBIDE driver to assist me, and a book
recomended by Rich Melchor)
- Hopefully, have a firmware that let me use the SD card as drive
MMC1, MMC2, etc.
- Improve the design to acommodate a flash EPROM. Add the necesary
logic into the CPLD to let the user burn new firmware inside this flash.
- As this will mean I have to use a bigger CPLD (the current one is a
XC9572XL-PLCC44, with all pins used), I probably add logic into it to
control the SPI clock speed, so the initialization sequence will be
consistent to the SD specification. I'm thinking of connecting the
rest of the SD pins so it would be possible in a future to use the SD
native mode transfer (4x faster) and support SD-HC cards. Currently,
the speed obtained is fast enough to serve data to a MC68008 at its
maximum speed (is there anything faster than 128 instructions move.l
(a1),(a0)+ to copy 512 bytes from the SD card to memory? )
- Betatesting phase.
- Available to the public
There's an open discussion thread (spanish) about the inner workings
of the interface (including some logic analyzer screenshots) here:
http://www.speccy.org/foro/viewtopic.php?f=15&t=2281
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Very impressive project!
Anton
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