Understanding USB

To have the data on a Compact-flash memory card, on a FAT file sytem, which you can just extract and put into a card reader or digicam for the PC to read out.

--
Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

"Richard Owlett" schreef in bericht news: snipped-for-privacy@corp.supernews.com...

Use a FTDI serial to USB convertor (like the FT232BM) with a virtual com port driver. With a very high baudrate, time to transfer that amount of data can be made acceptable, or use parallel mode which is just 8 lines and a strobe. You would need special software then.

Jeroen

If this is a one-time only thing, then the easiest is to get a PC serial card that can handle higher baud rates. If your black box can up it's transmit rate to the 1Mbaud region, then it would be almost

10x faster than the standard 115200 baud maximum. Even some of the "standard" PC Uarts support extended baud rates.

Regards Anton Erasmus

data

This begs some questions for me. I have a small embedded system that is using the FTDI FT232BM but experience a lot of problems when moving lots of data (at 115200 baud) that looks like data corruption at the bit level

0x2C -> 0x6C, 0x20 -> 0x40, 0x31 -> 0x71. This is data send from system to PC. There are bursts of about 30 kBytes or response to a short request from the PC. In other cases then there are smaller bursts in each direction (programming and verfication there are 1k bursts, CRC checked) there is no problem at all. Anybody else seen something like this? Any advice?

Peter

It is!

Links please. I've been casually involved with computers since days of 6J6's, KSR-33's, Hollerith key punch, etc. Please bear with antique who needs to adapt ;]

It hasn't been built yet :)

which?

Note: This may become moot as someone on another group has suggested a

*POSSIBLE* solution to my ultimate problem.

I would still appreciate responses to this tread as they may give hints at solving future problems.

thank you

You may want to consider the AT76C713. Most of the customers for this device started of with a USB/Serial ASIC or the FTDI. This has a UART w Hardware Flow control, FIFO + DMA support and on top of that an 8 kB internal databuffer. All is handled by a 48 MHz AVR allowing 921 kbps communication, no sweat.

Most competitor devices only have a couple of 100 bytes buffer and this is what I have seen caused problems with high datarates.

Runs a WHQL qualified driver and there is NO need to install a special driver on Win2k or WinXP. Should work off the shelf with any modern PC.

--
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may bot be shared by my employer Atmel Nordic AB

Exar, TI and others make PC Compatable UARTs that can handle much higher baudrates than the normal 115200 baud. Most Serial Coms Cards for PCs that are targeted more to the industrial end of the spectrum can handle the higher baudrates while remaining compatible with legacy PC Serial ports. On your "Black Box" Side. Most MCU Serial Ports devides the main CPU clock by a 16bit value to get the baud clock, hence with a 16MHz MCU clock you should be able to do 1Mb/s on most MCUs. If you use something that can do synchronous serial comms such as HDLC, you can go higher. For a simple ethernet solution look at the Wiznet W3100A Hardware TCP/IP interface chip. With very little software you can upload you data directly to an ftp server at > 1Mb/s.

Regards Anton Erasmus

I was just thinking of asking about practicality of using ethernet for a one shot project.

Browsed a few Google hits for "Wiznet W3100A" and it looks interesting.

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to

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Thanks Ulk. However I already have the hardware at third revision using a Sharp LH75410 and the FTDI device. There isn't an option for another processor at this stage. I am interested in how the AVR does this without a Win2k driver though because Win2k doesn't have drivers for USB->Serial even though there is a generic spec for it.

Peter