Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: aruna1 on May 08, 2013, 11:47:01 AM
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Hi
I recently designed a USB relay controller, and I have the prototype boards in my hand.
USB communication was intended to achieve through famous FT232RL chip.
I have soldered the MCU and FT232 and found out it is not working.
then I tried to see if FT232 is working properly by connecting RX to TX and doing echo test. test was a fail
Then I connected my logic analyzer to TX pin (pin 1) of FT232 and tried to capture its output while sending serial characters through USB.
according to the logic analyzer , output of FT232 is incorrect.
it lowers its output for the full length of the character and then set to high. this is same with any character.
then I tried changing chips but ended up with same result.
I have attached analyzer output and the schematic here.
Is there anything I'm doing wrong here? (this is my first time with FT232) any configurations needed?
or am I a victim of counterfiet ICs? (brought FT232 from chinese seller) (but FT_PROG can read and write FT232 chips EEPROM)
(LEDs are connected incorrectly, i noticed it after production of prototype boards. but I dont think that is the reason for this coz I checked the output after removing those LEDs)
(http://img716.imageshack.us/img716/1174/ftdii.png)
thanks.
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Maybe the problem is higher up the chain; are you sure your program is sending something other than 0? Does another FTDI chip send something other than 0 using that same program?
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counterfeit ics are pretty much an urban myth. ebay sellers wouldnt last a day.
to get your feet on the ground i suggest buying one of the $2-$3 usb serial dongles and seeing what comes out when typing in hyperterminal. you dont say what is being used now but seems like a good idea to separate the problem between hardware and software.