Hi Chris, thanks for the suggestions. I will try to use the the enable_bitbang function tomorrow and see if it works for me. The MorphIC-II has the JTAG pins of the Cyclone-II brought to a programming header, so I am using that one to program the FPGA, and also to "watch" the FPGA over signaltap. So there is no conflict with any other library on that PC, since I program the board from a different PC. When I tried to use the ftdi_set_bitmode function, I can see the FPGA going non-configured over the signaltap the moment this function is called, so I agree that something is changing the state of NCONFIG pin. I thought that by declaring that pin an input on the FT2232, it wouldn't affect the state of that pin, just as it didn't affect it when I used the ftd2xx library. I guess my point was that the ftd2xx library seems to work as I expected it to, but the ftdi library didn't.....
Cheers, Jo On 7/25/2011 7:54 PM, Chris Zeh wrote: > Hi Jo, > > I've been working on a project where I configure an FPGA (Cyclone II) > using the FT232RL, from my understanding the two are very similar to > communicate with. > > I mentioned in my blog post > (http://idle-logic.com/2011/03/05/programming-an-altera-cyclone-ii-fpga-with-a-ft232rl-python-code) > that I was having problems using the SetBitMode function, I don't > recall why but it wasn't working for me at the time. The documentation > said it's depreciated, but I ended up using the enable_bitbang > function instead and it worked for me. > > I'm curious what you're using to program the FPGA, a 3rd party > application? Possibly it uses the libftd2xx library and there is a > glitch on the handover to the libftdi library? > > If that NCONFIG pin gets pulled low you'll reset the FPGA into > configuration mode, which is what I'm guessing is happening. If you > set the NCONFIG to an output and keep it high does the device also > reset? > > Just throwing out some ideas... perhaps someone with more experience > can chime in :-) > > Best regards, > Chris Zeh > > On Mon, Jul 25, 2011 at 3:45 PM, Joachim Schambach > <[email protected]> wrote: >> Hi, >> I have a question about the usage of the ftdi_set_bitmode function. >> I am using a development board from FTDI called MorphIC-II to evaluate the >> usage >> of the FT2232HQ chip. This board uses the A port as an IO port to communicate >> with a Cyclone FPGA, and the B-Port is connected to the programming pins of >> the >> FPGA as follows: >> BD[0] = DCLK >> BD[1] = DATA0 >> BD[2] = NCONFIG >> BD[3] = NSTATUS >> BD[4] = CONF_DONE >> BD[7] = DEV_RST >> >> I am trying to use BITBANG mode to port B to set the DEV_RST line to 0, while >> leaving the other pins alone (by setting them as inputs). I have been able >> to do >> this with the libftd2xx library as follows: >> -----------ftd2xx code--------------------- >> ftStatus = FT_Open(1, &fthandle1); >> UCHAR Mask = 0x80; // only bit 7 is output >> UCHAR Mode = 1; >> // Set bit-bang mode >> ftStatus = FT_SetBitMode(fthandle1, Mask, Mode); >> UCHAR Value = 0x0; //set all bits to 0 >> ftStatus = FT_Write(fthandle1, &Value, 1, &BytesWritten); >> ------------end ftd2xx code ------------------- >> >> I am now trying to do the same thing with the libftdi library as follows: >> >> ----------libftdi code --------------------------- >> ftdi_init(&ftdic2) >> ftdi_set_interface(&ftdic2, INTERFACE_B); >> ftdi_usb_open(&ftdic2, 0x0403, 0x6010)); >> ftdi_set_bitmode(&ftdic2, 0x80, BITMODE_BITBANG); >> buf[0] = 0x0; >> ftdi_write_data(&ftdic2, buf, 1); >> -------- end libftdi code------------------------ >> >> But as soon as the ftdi_set_bitmode function is called, the FPGA seems to >> reconfigure, as if one of the other pins (other than pin7) gets toggled. >> >> Am I misunderstanding how to use the bitmask in this call? Or is there some >> other problem that prevents me from using this library with this chip? >> >> Regards, >> Jo >> >> -- >> Dr Joachim Schambach tel: x1 512 471 1303 >> The University of Texas at Austin fax: x1 814 295 5111 >> Department of Physics email: [email protected] >> 1 University Station C1600 >> Austin, Texas 78712-0264, USA >> >> >> -- >> libftdi - see http://www.intra2net.com/en/developer/libftdi for details. >> To unsubscribe send a mail to [email protected] >> >> > -- > libftdi - see http://www.intra2net.com/en/developer/libftdi for details. > To unsubscribe send a mail to [email protected] > -- Dr Joachim Schambach The University of Texas at Austin Department of Physics 1 University Station #C1600 Austin, Texas 78712-0264, USA (512) 471-1303, FAX: (781) 998-5513 email: [email protected] -- libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to [email protected]
