Im still confused about the form factor of this
product, you did shed some light on its capabilities (capacity, limits..) but
will this basically be in the form of a removable rom that can be re-written via
a usb interface device? in that case will it require that you open the command
station and pull the rom each time you wish to re-write? Also, if we do own an
ultra sampler, will it make this any easier/cheaper?
----- Original Message -----From: Jack PrattSent: Tuesday, February 16, 2010 2:04 PMSubject: [xl7] Re: FLASH SIMM
Unfortunately, it would not be useable in a max'ed out module. You would need to remove one of the existing SIMMs [making it no longer max'ed out...]It is useful for those who have one or more free slots on their module and want it to mirror all of the free slots (ie if you have two of your own SIMMs and you want it to act like two more then it can do that, or if you have no SIMMs at all it can be all four). It also would allow someone to make their own 'SIMMs' without the use of an ULTRA sampler.It would be as good as one or more existing SIMMs with the possibility in the future that it could be better than any existing SIMM as it could potentially be 'swapped' to another ROM image without opening the module [note that this would require changes to the OS in the proteus and because there's no guarantee that this will happen, no one should buy one of these with that expectation]Anyway, by way of an update - I have redone the schematic for the SIMM to include a CPU (SAM7S micro from Atmel) with a USB interface and an SDRAM chip (512Mb). There are two options for programming the SIMM through the SDRAM interface. Firstly I could make the SIMM look like a mass storage device to the PC with the ability to write on image. The image would be written to SDRAM and when you disconnect then the image is written to the appropriate region of FLASH. A bit cumbersome to write multiple images, no option for reading existing images... The second alternative is to have it appear to be a USB serial interface and have some communication protocol to allow the transfer of images to the FLASH without unplugging (then re-plugging) the USB connection. Also doesn't require the SDRAM chip on the SIMM (which is rather large). There are other options, but ones that require me to write device drivers are heavily deprecated.I haven't fully decided which one (or both) I'll implement so feel free to provide feedback.I've also almost completed the schematic for the programmer/reader board [necessary for programming if you have a SIMM without a CPU, alternative for programming if you have a SIMM with a CPU, necessary for reading existing SIMMs to figure out the storage format]. Its stalled slightly while I mull over how interactive it will be. That is, whether or not you just use it through the USB interface (which is simplest), or have the ability to use it stand-alone [ie be able to programm a SIMM from a compact FLASH card with some LCD screen for interactive selection of images to use].Probably the easiest is just have the SIMM CPU and the programmer CPU both have the same USB-serial interface so one interface fits all.Note that 'easiest' means quicker completion but limited options. Feedback (opinions) are welcome, but I reserve the right to follow my own counsel :-)Also done a PCB library for the major components, so should be able to work on the PCB layout soon...
From: Ivan Chaparro com>
To: xl7@yahoogroups.com
Sent: Sat, January 5, 1980 7:37:02 AM
Subject: Re: [xl7] Re: FLASH SIMM
Im in, just wondering if you could clarify how this would integrate into a maxed out command station. Eg: all four roms filled will i have to sacrifice one? will it just pop into one of the existing slots?