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Re: [xl7] Any interest remaining in a self-programming FLASH SIMM?

2014-07-16 by Jon Carroll

didn't the flash rom use a serial I/O to read the flash?

----- Original Message ----- 
From: "Jack Pratt woodsworth1@... [xl7]" <xl7@yahoogroups.com>
To: <xl7@yahoogroups.com>
Sent: Tuesday, July 15, 2014 5:07 PM
Subject: Re: [xl7] Any interest remaining in a self-programming FLASH SIMM?


the problem with the SD card is that the chips on the P2K can not inherently 
read it. So there would need to be some conversion from the SD card format 
to the memory mapped format used by the P2K. Of course if you put a micro on 
the board it could read from the SD card and rewrite FLASH as appropriate. 
Again you could use a special preset (accessing certain memory locations in 
the address map) to get the micro to copy one of any different ROM images 
into the FLASH based on which key is pressed. To let the user know when the 
copy is complete the "SIMM' could generate a stream of silence until the 
operation is over then produce a beep of some sort (if you are still holding 
the key down). If the new image(s) involve different presets/riffs etc then 
you would need to restart the P2K (because it only reads that information at 
startup).

but is this any better than doing it over USB?

You certainly wouldn't want to have the module opened to change the SD card 
all the time, and having a USB cable hanging out a hole seems an easy 
solution.

I believe that the preset ROM holds information that looks like the sysex 
infomation. Additionally I think that the wave ROM holds information that 
looks similar to the disk format of the E4/ultra series.

I am in the middle of writing software to dump the contents of a ROM SIMM so 
we can know for sure... will take a day or so.

!




________________________________
 From: "janoch23@... [xl7]" <xl7@yahoogroups.com>
To: xl7@yahoogroups.com
Sent: Tuesday, 15 July 2014 7:36 PM
Subject: Re: [xl7] Any interest remaining in a self-programming FLASH SIMM?




I only suggested dynamically modified samples, half jokingly, to get "global 
single-lfo rectangular pwm" and true noise say at waveforms #126 and #127. 
However, with 128 MB of sample ROM, you are much better off simply using 
samples for those, and not worrying about some clever scheme in the address 
decoder.

With regards to the micro on the SIMM, I think the other view is that having 
an SD card slot and figuring out the data format would be more useful since 
SD cards are cheap and abundant, and you'd have automatic compatibility with 
all kinds of PC operating systems via the ubiquitous card reader. This view 
doesn't really hold though because you'd be forced to open up your p2k / cs 
every time to pull out the SD card.

Personally I'd also worry that figuring out the data format is not simple at 
all and you'd risk having the project die out while people spend years 
trying to reverse engineer it, never fully figuring out every detail.

With your (Jack Pratt's) design at least everybody could duplicate existing 
ROMs and have something very useful "out of the box". Seeing how designing a 
large waveset is no mean feat, that would probably be the most useful.

---In xl7@yahoogroups.com, <woodsworth1@...> wrote :



The best way to do this (IMO) is to have a micro on the SIMM that will allow 
the FLASH to be 'reprogrammed' via USB. With appropriate software any image 
(existing or composed) could be transferred to the SIMM.


Finally the logic device can be used to provide access to on-the-fly sounds. 
However there are plenty of limitations to this.


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