FT232RL Loopback FAIL

[tedre191]

Hi,

I just receive my pcb from OshPark for my new project and i can't get the ft232rl chip working.
When I plug my board to my computer, drivers are installing and I can see the TX led light up when i'm sending data with Putty.

On a loopback test, RX and TX led light up but I receive only 0x00 values back.

Am I missing something ?

Thanks

[bobdagangster]

Unless I am mistaken, it generally helps to connect the RX/TX pins on the FTDI to the MCU... (Or maybe the net names are invisible in Eagle?)

[tedre191]

Sorry, my mistake. Indeed, RX and TX are connected to the MCU TX and RX, names are not visible in that screenshot.
To do my loopback test, I removed the MCU and  connected pin 1 and 5 together. I tried with and without the two 1k resistors.

[bobdagangster]

I tried with and without the two 1k resistors.

I was about to suggest that...
CTS might want to be pulled up?

[fcb]

Download "FT_prog" from the FTDI website, have a look at how things are configured (the FT232R has onboard EEPROM).

It should be trivial to join TX & RX and use something like Hyperterminal to loopback - you may have flow control setup??

[tedre191]

CTS might want to be pulled up?

I just tried, didn't work.

Download "FT_prog" from the FTDI website, have a look at how things are configured (the FT232R has onboard EEPROM).

It should be trivial to join TX & RX and use something like Hyperterminal to loopback - you may have flow control setup??

Flow control is set to "None". I downloaded FT_prog and i'm able to read the FT232R EEPROM content.

None of the options in "Hardware Specific" are enabeled.
I'm probably missing something .. 

[David_AVD]

Did you buy the chip from a known source or eBay / AliExpress?  There are dodgy fakes doing the rounds if I recall correctly.

[tedre191]

Did you buy the chip from a known source or eBay / AliExpress?  There are dodgy fakes doing the rounds if I recall correctly.

I bought the chip on eBay (2 of them, both the same issue).
http://www.ebay.ca/itm/140838941057

[richcj10]

You got fake chips.

[mickpah]

You got fake chips.

yep very likely, I bought a board from Itead , same issue. They admitted they had been caught with fakes. They replaced it.  The QC sticker must have been for the board only I guess

[sleemanj]

RTS and CTS are active LOW, either pull them down, or link RTS to CTS so it's signalling itself.  Don't know if it will help, but worth a try huh.

[David_AVD]

No need to do anything with the control lines.  Hooking up tx and rx is all you need for a basic connection.

[amyk]

You got fake chips.

Or just defective...

[tedre191]

Thanks everybody, I'm gonna buy new chips (from Digikey this time) and give them a try.

[tedre191]

Just received my new chips from Newark and everything is working now. Thank you all for your help !