Author Topic: Need help with FT232RL  (Read 1626 times)

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Offline aruna1Topic starter

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Need help with FT232RL
« on: May 08, 2013, 11:47:01 AM »
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)

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Offline jwatte

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Re: Need help with FT232RL
« Reply #1 on: May 08, 2013, 01:33:50 PM »
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?

Offline johnwarfin

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Re: Need help with FT232RL
« Reply #2 on: May 16, 2013, 06:56:26 AM »
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.


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