USB PHY question

[europus2002]

Hi All,
Has anyone dealt with FT245BM like USB phy layer chips?? I am having problems in a freshly designed prototype. The website says things very simply and drivers and the EEPROM software has too many problems settling down without success . Here's what happens
1) As soon as i turn on my prototype and connect USB cable, the comp has long message that says " device malfunctioned on the port" (in short) etc....I checked all my schematic , hardware, board and component values & they are what they should be. Also cross checked with other ppl's schematic online and they are in sync....The device shows up in the Device Manager as" Unknown device" under USB hub(driver missing).
In the USB enumaration , i checked and correlated with other working USB device (USB mass storage HDD) , the signalling etc has same looks (3-0V NRZ Typ). But the burst last for only couple of seconds in my case where as it goes on for other devices like USB webcam and USB Hdd..... I figured out the issue could be with my EEPROM chip not programmed (that's what the programmer s/w is suppose to do) . In the USB view(utility for viewing USB enumaration) , it shows VID & PID both 0x00......So i remove the EEPROM....But no change in comp response....I am now confused and no response from tech's from the manufacturer ......Does any one have a clue as to what could be wrong......I forcibly tried to load the driver, but created problems with my comp.....thanks in advance guys...

 

[zappedagain]

Are you still working on this? We recently used an FT232 in a design and it worked like a charm.

You might check out a 'FT245 Tinyboard' from

http://www.siphec.com/Misc/index.html

That will give you a functional reference design that you can probe against.

 

[europus2002]

Hi Zappedagain,
Thnaks a lot for your help. I found the problem to be with the crystal that we used. It would intermittently stop oscillating(could be reflow problem). So i added an external oscillator. Now it works like a cake. Also had couple of applications giving me an error and i changed the 27ohm resistor values (recommended in datasheet) back to 10 ohm(value from old datasheet) and those errors too stabilised......But i liked the board u sent me the link for and wouldn't mind ordering couple of them .how much is it priced for per unit???

 

[zappedagain]

I don't know; I haven't used a Siphec board. I'm glad to hear you got things working.