Re: [avrdude-dev] FT2232H-based programmers

[Ing. Daniel Rozsnyó]

On 06/10/2013 10:03 AM, Hannes Weisbach wrote:
> Am 09.06.2013 um 18:26 schrieb Дмитрий Головин:
>
> > Hi,
> >
> > I saw avrdude 5.11 release with MPSSE support and thought it would be very 
> > fast. I ordered the FT2232H Mini-Module and now I received it. Having this tiny 
> > thing is cool, but I don't know what to do with it (I'm pretty new to all this, 
> > really).
> > To test MPSSE I need to somehow connect my FT2232 to target AVR. I looked up in 
> > /etc/avrdude.conf and found out that FT2232 pin numbers are just numbers and 
> > and in FT2232 datasheet it's legs have different name: {A,B}{C,D}BUS{0-7}. So 
> > how do I connect it?
> TCK/SK (ADBUS0) goes to the SCK pin.
> TDI/DO (ADBUS1) goes to the MOSI pin.
> TDO/DI (ADBUS2) goes to the MISO pin.
> You are free to use which ever free pin you want for RESET. I use TMS/CS 
> (ADBUS3).
> The at the end of ADBUSn is the pin number in the avrdude.conf file. If you 
> encounter a new letter you just keep on counting. For example ACBUS7 becomes 
> pin 8 in avrdude.conf.

This is valid just for AD+AC bus, for that  usbdev = "A"; is specified 
in the programmer. For the BD+BC bus, count again from 0 to 15, with 
usbdev = "B".

> The first three pins have a fixed function and cannot be changed. (You can 
> change them, but then it won't work anymore.)
> > There is also a buffer IC (74AC244) mentioned in config file. Is it optional or 
> > not?
> It's optional.
> > If not, what other buffer ICs may be used?
> Anything with the proper voltage ratings for input and output.
> > If it is optional, what is it for and what is it's benefit?
> ESD protection, driving capacitive loads (long cables).
> > And what does "active low" (about LEDs) mean? Should led be placed between 
> > FT2232H output and GND or VCC?
> 'active low' means the pin to which the LED is connected has to be low for LED 
> to be active (i.e. lit). So you have to connect the other end of the LED to 
> VCC. Don't forget a current limiting resistor (1k to 10k) in series to the LED 
> and point the LED in the correct direction.
> > And the last question to the owners of this Mini-Module. In manual it is said 
> > to connect VBUS to VCC. Is it a good idea to connect it through additional 
> > voltage regulator (AMS1117-5.0V) in case USB power is more than 5V?
> No. The FT4232H Mini-Module has an on-board voltage regulator MIC5219 which can 
> already handle up to +12V (+-20V maximum rating). I assume the FT2232H 
> Mini-Module has one too.

Yes it has, you need to connect VCC somewhere - to VBUS if you want to 
operate the module from usb power, or to your applications power supply 
(at lest 5V, with 3.3V it wont work here). Mine has a AIC1733-33 regulator.

> > It is also said to connect V3V3 to VIO. Should I connect it to all four VIO 
> > pins or just one of them?
> All of them. Read the FT2232H datasheet.

You have to connect all of them, since the minimodule board layout is 
just 2 layer and the VIO pins are not connected on the board. By looking 
to schematics of the module one would assume they are connected on the 
PCB, but they are not.

> Best regards,
> Hannes
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