hi, I have a Moprh-IC-II board and I'm trying to communicate via USB with a FT2232H in Sync FIFO Mode and D2XX Drivers. I manage to have the 60MHz clock input (my main fpga clock) from the ft2232h, and i can transfer data from the PC to my fpga via ft2232h with FT_Write(). FIFO Mode seems to work as expected on this side. The RXF# signal is working, going low when needed (I'm checking signals with SignalTap). But I can't send data from my fpga to the pc, the TXE# signal (active low) is stuck high and I can't find how to have it low to be able to receive data... If you have any idea on what my issue could come from ? Tank you, Alexis

Check here http://electro-logic.blogspot.it/2014/03/fpga-comunicazione-ad-alta-velocita_99.html?m=1

I can't say for sure, I've used the FT2232 many times and not had this problem. Have you checked the obvious, TXE# is connected to an FPGA input pin and not an output being driven high? Have you tried clearing the transmit buffer with FT_Clear()? Have you actually issued an FT_Read()? Does the FT_Read() come back with an error, timeout, etc? What is your host system/OS?

Hi, --- Quote Start --- Have you checked the obvious, TXE# is connected to an FPGA input pin and not an output being driven high? --- Quote End --- Already checked, I proceeded the same way (with a different name of pin obviously, according to the datasheet) with TXE# and RXF# and RXF# works perfectly. --- Quote Start --- Have you tried clearing the transmit buffer with FT_Clear()? --- Quote End --- If by FT_Clear you mean FT_Purge without success, I've tried this (can't find any FT_Clear in the D2XX Programmer's guide). --- Quote Start --- Have you actually issued an FT_Read()? Does the FT_Read() come back with an error, timeout, etc? What is your host system/OS? --- Quote End --- I can call FT_Read() without any error but I will always have 0 BytesReceived (even if I ask to read several bytes), which is kind of normal because FT_GetQueueStatus always says there is nothing in the receiving buffer. TXE# high telling me the ft2232h is never ready to receive any data. I'm on Windows7 (32-bit). I load my fpga by USB through the channel B of my fifo with the MorphLd Utility, could this be somehow related? Edit : loading fpga by JTAG doesn't change anything. Many thanks for your help, I'm kind of new to this whole thing. Alexis

Hi, --- Quote Start --- Check here http://electro-logic.blogspot.it/2014/03/fpga-comunicazione-ad-alta-velocita_99.html?m=1 --- Quote End --- I've already checked this useful blog, but I can't find what I did differently in my Software part, which I suppose being where my problem come from (receiving buffer not ready to receive). I'm using D2XX drivers and not libftdi this shouldn't make a huge difference... Here are my actions when trying to configure my device : - FT_OpenEx - FT_ResetDevice - FT_Purge - FT_SetBitMode - Reset Mode - FT_SetBitMode - Sync FIFO Mode - FT_SetLatency - 2ms - FT_SetUSBParameters (64 Bytes each) - FT_setTimeOuts Alexis

Do you realize that in Sync FIFO mode the FT2232 is a single channel device? When you load your fpga through channel B it must somehow reconfigure the FT2232 for dual channel mode. Are you sure you're switching back to single channel when you try to run in sync FIFO mode?

FT2232H in Sync FIFO Mode - TXE# stuck high

17 Replies

Altera_Forum
Honored Contributor
9 years ago
I've not worked with the hardware in some time, so I couldn't say exactly when TXE# goes low.
Altera_Forum
Honored Contributor
9 years ago
Hi,

--- Quote Start ---
Here's some of the code I used to configure channel A for sync fifo mode. Maybe something will stand out.

UCHAR Mask_A = 0xff; // all outputs
UCHAR Mode_A = 0x40; // high speed synchronous fifo
UCHAR Reset_Mode = 0x00;
UCHAR LatencyTimer = 2;

// connect with Channel A and set Mode
ftStatus = FT_Open(device_number_a, &FTDIHandle_A);
FT_SetBitMode(FTDIHandle_A, 0xff,Reset_Mode);
Delay(.01);
FT_SetBitMode(FTDIHandle_A, Mask_A,Mode_A);
FT_SetLatencyTimer(FTDIHandle_A, LatencyTimer);
FT_SetUSBParameters(FTDIHandle_A,65536,65536);
FT_SetFlowControl(FTDIHandle_A,FT_FLOW_RTS_CTS,0x00,0x00);
FT_SetTimeouts(FTDIHandle_A, 5000, 5000);
--- Quote End ---

TXE# should obviously be low after this kind of settings or am I missing / misunderstanding something ?

Alexis.
Altera_Forum
Honored Contributor
9 years ago
Hi,

SOLVED :
I'm not using the "USB Remote WakeUp" mode, and the master I had taken from the FTDI project of AN_165 was completely ignoring the pin SIWU.
At first sight, it seemed quite ok and I didn't question it.
BUT, when unused, the SIWU pin has to receive '1'...

PS: is it possible to mark a thread as Solved in alteraforum?

I'd like to THANK YOU gj_leeson for everything you've done to help me!

Alexis.
Altera_Forum
Honored Contributor
9 years ago
I'm glad you solved your problem. I didn't even think about the SIWU pin as I've always tied it HI.
Altera_Forum
Honored Contributor
9 years ago
Hi,

Do you know the datarate you've reached with this setup ?

I've reached 32MBytes/s this far, but the size of buffers or the data latency timer don't seem to change anything on my datarate.

Alexis.
Altera_Forum
Honored Contributor
9 years ago
For big transfer buffer size and data latency doesn't affect speed.
For small transfer I set latency to 1 ms and use SIWO. Key to improve performance is to make less bigger Write call to use less USB microframe.
I reached 50 MB/S in read and 14 MB/S in read (see last image into http://electro-logic.blogspot.it/2014/02/fpga-comunicazione-ad-alta-velocita_16.html)
Altera_Forum
Honored Contributor
9 years ago
Thank you for your feedback.

Is it normal not to receive those "2 status bytes" that I've read about in many datasheets about usb transfer ?

Alexis;

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FT2232H in Sync FIFO Mode - TXE# stuck high

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