libftdi Archives

Subject: Re: FT2232H question

From: Uwe Bonnes <bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: libftdi@xxxxxxxxxxxxxxxxxxxxxxx
Date: Sat, 6 Apr 2013 12:39:06 +0200
>>>>> "Thomas" == Thomas Heller <theller@xxxxxxxxxx> writes:

    Thomas> Sorry for this off-topic question, but I want to use the FTDI
    Thomas> knowledge in this forum:

    Thomas> I use a module (DLP-HS-FPGA) which has an FT2232H chip connected
    Thomas> to a Spartan3A FPGA.  One channel of the ftdi chip is used to
    Thomas> program the SPI-Flash, the other channel is used to communicate
    Thomas> with the FPGA.

    Thomas> The former channel has one pin connected to the PROG_B pin of
    Thomas> the FPGA, to force a reload after programming to flash, by
    Thomas> pulsing this pin low.

    Thomas> Unfortunately, this pin as also pulsed low when the
    Thomas> USB-connector is removed and reconnected to the PC - which
    Thomas> causes a reload of the FPGA but I do not want this.

    Thomas> The suggestion from the manufacturer was to break the connection
    Thomas> between the FT2232H pin and the PROG_B pin.  This no longer
    Thomas> causes a reboot of the FPGA, but the downside is that I have to
    Thomas> power-cycle my board after programming the flash to force a
    Thomas> reload of the FPGA.

    Thomas> All in all, I need a way to pulse the PROG_B pin low
    Thomas> programmatically from the PC (over USB), but the PROG_B pin must
    Thomas> stay high when the board is disconnected and reconnected
    Thomas> (without losing power) from the PC.

You can pulse prog_b via JTAG access to the FPGA.

xc3sprog https://ethernut.svn.sourceforge.net/svnroot/ethernut/trunk should
do that allready. You can also program the SPI flash via the FPGA and
bscan_xx_spi.

Bye
-- 
Uwe Bonnes                bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------

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