Problem with USB port

Not when one can print a few hundred billion dollars more...

Ditch the pic, Port him to a Atmel Mega8 series and use Objective Developments USB code. Its known to work.

Having spent the last few months developing a USB 12 bit joystick for a flight simulator , I can personally attest there is a lot of USB garbage out there, most of it poorly documented and poorly tested.

Steve Roberts

Yes - so frightening that as a designer I won't go anywhere near safety critical systems. There's too much legal baggage involved. This even applied when I was working at a consultancy based in a major UK university, with all the indemnities and insurance in place.

they guy's using a usb to serial interface chip and it's not running right, the problem's not usb code in the pic as there is none, possibly it's a crystal or other capacitance sensitive part that's misbehaving now the circuit's out of breadboard.

I'm glad to hear your reports on avrusb as I have a project for which it seems ideal myself...

Bye. Jasen

The software USB is another can of worms. Timings is very critical and only work on low speed USB.

It's most likely software problem with the FTDI245. The FTDI245 does not have A2D and the PIC does not have USB. However, there are plenty of other chips with A2D and USB. That's why I said it was the technician's problem of picking parts, and the managing doctor's problem of not evaluating other options.

I suggest ATmega16U with 16K Flash, 1K Sram, 12 10 bits A2D and USB

Printed dollars, hah! Most of the "money" circulating today is just computer data. The printing is no more than computer data entries.

I checked your website, it is ok. You seem to have some experience at medium voltage (~5 kV to ~50 kV). I am reviewing a proposal that includes 5kV and 15kV cables that can operate at 200 C ambient (well outside of the ratings of MV-105). They are proposing TGGT insulation rather the usual EPR or XLPE for the cable insulation layer. I could not find anything that could meet these requirements. Do you know of anything?

My experience is almost exclusively with low voltage (480 VAC) and high current (up to 100,000 amps). I've only done a little HV work with insulation testers and HiPots. The reclosers that are tested on the machine (ORT-15) for which I got a patent, are used in medium voltage applications, but are tested using low voltage. I do have customers who might have experience with medium voltage cables, but I don't know them personally.

You might try the newsgroup:

sci.engr.electrical.sys-protection

Paul

I don't understand why the XLPE wouldn't be ok, after the irradiate process, that material can withstands a solder pot test or directly be wrapped around a heated fired rod at 550F with no damage.

Maybe they're are some other factors involved here?

I would think XLPE would be more economical.

I'm using the FT245BM FIFO. This device has an ugly behaviour. After each byte you have to check the "FIFO Empty" (TXE#) line. But this line changes its state about 300...500ns after the last byte was written! If you check the line immediately after you have written a byte, and its low (=space left in FIFO) the next byte you write will be lost! You must wait until this line changes to high and then low again for each byte!

jbe

Thanks for that tip!

The datasheet says the TXE# line will change to high (=FIFO full) for each byte you write and low again if there is free space in the FIFO. And it says the FIFO does not accept new bytes until the TXE# line is low. But it does not say that it will change so late after each write! Writing 4 bytes to the FIFO takes about 2us to do so (but the datasheet suggests you can do it in about 200ns, 50ns per byte).

jbe