USB Breakout

I agree entirely, but the customer concerned doesn't want the increase in size that the upgrade would bring and they are one of our biggest customers.

}{ a écrit :

You could see what you can do with this protocol analyser and pattern generator, or perhaps ask the customer support.

Ulf Samuelsson wrote about someone's need to diddle the contents of a data stream between a USB host and device:

Probably OK as long as the bandwidth isn't approaching the limit and you're not worried about isochronous transfers.

The Cypress EZ-Host (CY7C67300) and EZ-OTG (CY7C67200) also come to mind, for compact, low-cost solutions. They each have two USB SIEs that can each be configured as device or host. They can boot from an I2C EEPROM. The main drawback is that they use the Cypress CY16 core, so there aren't many choices for development tools. On the other hand, they're very inexpensive.

Have some customers using the board, so maybe you need to be nicer to Tsvetan.

I've had good results with one of these:

Andy

:-)

not sure what I have to do Ulf. Trouble is his boards are too popular. I just keep ordering what customers request, and hope they come.

Explained at:

Cheers Don...

pt

Cant you use a usb to rs232 converter, pic, rs232 to usb converter. You can get them ready made or just use the chips.

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The USB part of the RS232 converter has to connect to a PC or other host device that can handle all the enumeration and control signals. IIRC, the device described by the OP, has only one host and one slave device---not the two hosts your converters would require.

Mark Borgerson

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For the sake of arguing, you can use a usb device to rs232 converter (ftdi), pic and rs232 to usb host converter (avr).

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I think you'd still have to program the PIC and AVR. I don't know how hard it is to get the AVR to mimic the host to which the device is to be connected. Still looks to be more complex than intercepting the signals outside the USB chain.

Mark Borgerson

It wouldn't work anyway except in the most specific of cases. Assuming that speed is not a restriction, which itself is a big if, USB and RS232 are fundamentally different protocols. USB has multiple transfer modes and multiple endpoints defined even for a simple link between host and device with no hubs involved. RS232 doesn't, and you can't add these on with a regular USBRS232 interface chip because it simply isn't what the devices are designed to do. Added to that such a hack would appear to the host to be a USB RS232 port, not whatever device it is you need to interface to.

The only time I can see this approach working is if the device itself uses an RS232USB interface internally which is at least possible, but in that case you have your entry point there - break into the signals at the RS232 stage within the device itself.

I don't really have any suggestions in the general case though. A device to do what the OP wants would have more in common with a hub than anything else, but again this isn't what your standard off-the-shelf hub designs are designed to do and I doubt they could be adapted to serve this particular purpose.

I doubt that any COTS USB hub chip would have this functionality, but if you could get a hub as an ASIC core, you could add the necessary "breakout" processing. A hub is already able to connect to a host upstream and multiple devices downstream. AFAIK, a hub simply passes data through with no buffering, so any "breakout" decision has to be made at full bus speed. Just buying the core IP is probably a 4 or 5 figure NRE. Bringing your knowledge from PIC/RS232 up to ASIC design is certainly another 5 or 6 figures.

Of course, the engineering solution is to fix the software, not kludge the hardware.

Bob

I plan to start this MSc this year, this may well be a silly question, but could anyone give me their thoughts regarding course syllabus and how it relates to the real world

I have already passed this back to the design team.