Hi All, I am looking at a project which needs removable memory. This is going inside an industrial control system and will be moved in-frequently. Being an amateur photographer I though CF (Compact Flash) It is easily available up to 8GB at the moment and is physically easy to handle. Some one else suggested SD cards as they are smaller and as CF is "old" it might disappear soon. Has any one else any views on the life expectancy of the CF and SD formats? I don't like SD as it is usually in a spring loaded holder and if knocked flies out (not clever in an industrial system) Also it is somewhat smaller and less easy to handle in when trying to fit it inside a box in inaccessible parts of a factory. Does any one have any suggestions for a reliable high capacity removable solid state memory (no NOT USB that has already been discounted) -- \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/ /\/\/ chris@phaedsys.org www.phaedsys.org \/\/\ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
Which removable memory
Started by ●January 5, 2008
Reply by ●January 5, 20082008-01-05
Chris H wrote:> Hi All, > > I am looking at a project which needs removable memory. This is going > inside an industrial control system and will be moved in-frequently. > > Being an amateur photographer I though CF (Compact Flash) It is easily > available up to 8GB at the moment and is physically easy to handle.I am using CF for the same reasons you mentioned. It is the fastest and the highest capacity card so far.> Some one else suggested SD cards as they are smaller and as CF is "old" > it might disappear soon. Has any one else any views on the life > expectancy of the CF and SD formats?Probably it will be the shift in camcorders from the MiniDV cassette to a flash card. Unless they will introduce something new, the CF looks like the best candidate.> I don't like SD as it is usually in a spring loaded holder and if > knocked flies out (not clever in an industrial system) Also it is > somewhat smaller and less easy to handle in when trying to fit it inside > a box in inaccessible parts of a factory. > > Does any one have any suggestions for a reliable high capacity removable > solid state memory (no NOT USB that has already been discounted)The USB drive could be handy however it requires the USB 2.0 hardware and the cumbersome host software stack. The VNC1L USB host from FTDI is simple, but very slow: you can only get 300kbytes/sec at the very best case. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●January 5, 20082008-01-05
In article <0vJn3fHBT5fHFAaf@phaedsys.demon.co.uk>, chris@phaedsys.org says...> Hi All, > > I am looking at a project which needs removable memory. This is going > inside an industrial control system and will be moved in-frequently. > > Being an amateur photographer I though CF (Compact Flash) It is easily > available up to 8GB at the moment and is physically easy to handle. > > Some one else suggested SD cards as they are smaller and as CF is "old" > it might disappear soon. Has any one else any views on the life > expectancy of the CF and SD formats? > > I don't like SD as it is usually in a spring loaded holder and if > knocked flies out (not clever in an industrial system) Also it is > somewhat smaller and less easy to handle in when trying to fit it inside > a box in inaccessible parts of a factory. > > Does any one have any suggestions for a reliable high capacity removable > solid state memory (no NOT USB that has already been discounted)My last system uses a MicroSD/TransFlash card in a latching hinged carrier. It requires a very specific action to remove the card, and survived vibration testing with flying colors. Here's the Mouser catalog page link (item "L"): http://www.mouser.com/catalog/632/1260.pdf Note that I found that some manufacturers' MicroSD cards do not operate correctly in SPI mode. They are TINY, and we didn't design it to be removed frequently (we expect the User to download the data). --Gene
Reply by ●January 5, 20082008-01-05
On Sat, 5 Jan 2008 14:31:29 +0000, Chris H <chris@phaedsys.org> wrote:>Hi All, > >I am looking at a project which needs removable memory. This is going >inside an industrial control system and will be moved in-frequently. > >Being an amateur photographer I though CF (Compact Flash) It is easily >available up to 8GB at the moment and is physically easy to handle. > >Some one else suggested SD cards as they are smaller and as CF is "old" >it might disappear soon. Has any one else any views on the life >expectancy of the CF and SD formats? > >I don't like SD as it is usually in a spring loaded holder and if >knocked flies out (not clever in an industrial system) Also it is >somewhat smaller and less easy to handle in when trying to fit it inside >a box in inaccessible parts of a factory. > >Does any one have any suggestions for a reliable high capacity removable >solid state memory (no NOT USB that has already been discounted)Just curious - why has USB been discounted ? The Vinculum VNC1 chip makes it very easy to interface to now, and having only 4 pin connections to worry about is probably good in an industial environment. The other big advantage of USB is that every PC has a read/writer built in!
Reply by ●January 6, 20082008-01-06
In message <hq30o39g1vocepepaftpgbg484u8i2ndvp@4ax.com>, Mike Harrison <mike@whitewing.co.uk> writes>On Sat, 5 Jan 2008 14:31:29 +0000, Chris H <chris@phaedsys.org> wrote: > >>Hi All, >> >>I am looking at a project which needs removable memory. This is going >>inside an industrial control system and will be moved in-frequently. >> >>Being an amateur photographer I though CF (Compact Flash) It is easily >>available up to 8GB at the moment and is physically easy to handle. >> >>Some one else suggested SD cards as they are smaller and as CF is "old" >>it might disappear soon. Has any one else any views on the life >>expectancy of the CF and SD formats? >> >>I don't like SD as it is usually in a spring loaded holder and if >>knocked flies out (not clever in an industrial system) Also it is >>somewhat smaller and less easy to handle in when trying to fit it inside >>a box in inaccessible parts of a factory. >> >>Does any one have any suggestions for a reliable high capacity removable >>solid state memory (no NOT USB that has already been discounted) > >Just curious - why has USB been discounted ?The USE interface is being used for something else.>The other big advantage of USB is that every PC has a read/writer built in!That is not an advantage in this case. -- \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/ /\/\/ chris@phaedsys.org www.phaedsys.org \/\/\ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
Reply by ●January 6, 20082008-01-06
Un bel giorno Mike Harrison digit�:> Just curious - why has USB been discounted ?USB is *very* bad for noisy environments (automotive, industrial etc). It's the main source of problems in every single automotive product we equipped with it. -- emboliaschizoide.splinder.com
Reply by ●January 6, 20082008-01-06
In message <1bkv35220231r$.7ecysnlhjkwi$.dlg@40tude.net>, dalai lamah <antonio12358@hotmail.com> writes>Un bel giorno Mike Harrison digit�: > >> Just curious - why has USB been discounted ? > >USB is *very* bad for noisy environments (automotive, industrial etc). It's >the main source of problems in every single automotive product we equipped >with it.Many thanks for that. -- \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ \/\/\/\/\ Chris Hills Staffs England /\/\/\/\/ /\/\/ chris@phaedsys.org www.phaedsys.org \/\/\ \/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
Reply by ●January 6, 20082008-01-06
On 2008-01-06, dalai lamah <antonio12358@hotmail.com> wrote:> Un bel giorno Mike Harrison digit�: > >> Just curious - why has USB been discounted ? > > USB is *very* bad for noisy environments (automotive, > industrial etc). It's the main source of problems in every > single automotive product we equipped with it.It also requires _massive_ amounts of SW overhead. A host USB stack is many hundreds of KB. -- Grant Edwards grante Yow! at BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI-BI- visi.com
Reply by ●January 7, 20082008-01-07
Grant Edwards wrote:> On 2008-01-06, dalai lamah <antonio12358@hotmail.com> wrote: >> Un bel giorno Mike Harrison digit�: >> >>> Just curious - why has USB been discounted ? >> USB is *very* bad for noisy environments (automotive, >> industrial etc). It's the main source of problems in every >> single automotive product we equipped with it. > > It also requires _massive_ amounts of SW overhead. A host USB > stack is many hundreds of KB. >The Vinculum VNC1 chip would avoid some of Chris' problems (it doesn't matter that his existing USB interface is used for something else, and there is no need to worry about the host software since it is integrated in the chip). Of course, noise may still be a problem - although it would be much less if the USB flash drive is attached directly and there are no long wires. The reported 300 KB/s speed may or may not be a problem, depending on the needs of the application. I haven't tried the VNC1 myself, but I'm a happy user of other FTDI devices, and we may use the VNC1 in future products.
Reply by ●January 7, 20082008-01-07
On Jan 5, 9:31 am, Chris H <ch...@phaedsys.org> wrote:> I don't like SD as it is usually in a spring loaded holder and if > knocked flies out (not clever in an industrial system) Also it is > somewhat smaller and less easy to handle in when trying to fit it inside > a box in inaccessible parts of a factory.I would go with SD given the ease of SPI interfacing and low commodity prices. And then I'd probably do something like put a screw-on cover over it. I bet you could also figure out how to remove the ejector spring so that it was push-in pull-out. Another option you could consider - more costly but perhaps more durable - might be to make a custom cartridge using an SPI flash device on a tiny board. This could be in a two piece aluminum housing or something quite durable like that. Actually, if numbers are low, another option is to put an SD card in there and solder wires between the SD pads and your external connector!
