VINCULUM

BTW, I apologize for the multiple posting. I thought the message didn't go through for the first time because the product name seems to be related to the canadian pharmacy. So it was killed by the spam blockers.

:-)

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

No relevant experience, but what a terrible product name. It sounds like it ought to be some kind of putrid glandular secretion. 8-(

Best regards, Spehro Pefhany

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Below is a snippet of info I got 2 hours ago. I have kept the message exchange basically intact so that it can't be read out of context

Don...

====================================================== Questions from customer:

My target design is to have 2 USB ports: 1 host, 1 slave

1 Host to write (datalog constantly actually) to a standard/common USB memory stick 1 Slave to allow a communications data stream to a PC Host (virtual com port or similar serial data stream method)

I see the VNC1L has a VDPS firmware package that may allow this functionality,

1. Is the VNC1L with VDPS firmware exactly what I am after as per the above?

1. Any royalty or licensing things I should know about?

2. Will it support without performance or other issues, simultaneous file writing/streaming out to a USB memory stick on the 1 host port, while also doing communications to a PC via the 1 slave port?

1. What is the actual write performance to a USB memory stick, how many bytes/second minimum should I be able to rely upon for datalogging purposes to write out to a USB memory stick? I know USB memory sticks come in different flash write speeds, but any info you could give me would be very helpful.

2. What kind of reliable throughput can I expect for communications on the 2nd port (enumerated as FT232 I believe?) while the first port is writing very frequently to a USB memory stick in host mode?

==========================================================

Reply from support:

Hello,

I'm not sure that the firmware can perform the way you would like. You will not be able to write data to a flash disk and have data streaming through the slave port at the same time.

Because the VNC1L has to go into data mode to stream data using the slave port you will be unable to send commands to the VNC1L during this time. Data mode works by passing data from the port straight to the PC bypassing the VNC1L. After you return from data mode to command mode you will be able to communicate with the VNC1L and therefore be able to send data to the flash disk.

When writing data to a disk the VNC1L will have to locate a free cluster before data can be stored. The writing speed will depend on the flash disks cluster size and the speed of the flash disk.

The speed of the slave port should run at a maximum of 3M baud where the limiting factor is the monitor port of the VCN1L.

Regards,

xx Support Engineer

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Don McKenzie

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Serial OLED uses standard micro-SD memory cards.
http://www.dontronics-shop.com/product.php?productid=16659

USB Flash Drive interface for existing products.
http://www.dontronics-shop.com/product.php?productid=16654

Possible duplicate response, google problems....

I would think that the maximum speed would depend on which interface is used to the host computer. We looked at it for a data logger application but we require operation down to -40C and the Vinculum is only available in the commercial temperature range.

I have a uALFAT board on order from

and it would it's major limitation is in the SPI interface (it doesn't have a FIFO interface) which must be clocked "at less than 8mhz". I might have more info next week.

Vladimir Vassilevsky wrote in news:CXHui.32643$ snipped-for-privacy@newssvr14.news.prodigy.net:

I have two VDRIVE's and I can only say that they work as advertized. I didn't look yet to their throughput performance. I hope FTDI issues a development kit for the chip, I can't wait to run my own apps on it!

Sam

you mean something like this:

Don...

-- Don McKenzie

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Serial OLED uses standard micro-SD memory cards.

USB Flash Drive interface for existing products.

Don McKenzie wrote in news:46bc133d$0$18984$afc38c87 @news.optusnet.com.au:

Yes, and I want to change the f/w on the VNC1L !!

Sam

My first association with the name:

The articile also gives the meaning of this latin word. This meaning seems to suit the IC. You wonder where they got the name from: A startrek episode or a latin dictionary. ;-)

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Stef    (remove caps, dashes and .invalid from e-mail address to reply by mail)

I have got the confirmation from FTDI that somewhat 300kbytes/sec is about maximum transfer rate that you can achieve with VNC1L and USB flash. Very slow indeed :(

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

Was that for read or write? For UART, SPI or parallel?

It is the very maximum R/W sustained speed limited by the overhead of VNC1L itself. Other overheads are making it even slower than that.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant

Un bel giorno Vladimir Vassilevsky digitò:

Probably it's adequate for the typical application for this kind of devices: data logging with moderate yet continuous throughput (sensors, diagnostic events, etc). Then you extract the usb key and read it with a PC.

IIRC the same problem applies also with the FTDI's usb client devices (FT245R and friends). Some time ago I looked for some device able to give me uber-speed (I don't ask for all the USB 2.0 high-speed bandwidth, but at least some MB/s) but at the same time that acts like a simple FIFO like FTDI devices. The closest match was something based on (guess what?) Cypress EZ-USB:

But it has a lot of drawbacks (for starters, it costs *way* too much). My conclusion was that it would have been better to develop my own EZ-USB firmware. Maybe now there is something new I don't know?

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