Hi,
I can activate the four modes on a FT4232H, but there is some strange
clock inversions at each bytes for cpol=0, cpha=1 and cpol=1, cpha=0
modes.
You can look at the code of my lib on http://code.google.com/p/libftdispi/
Extract from ftdispi.h :
- CPOL=0 CPHA=0 => Mode 0, W=FE R=RE
- CPOL=0 CPHA=1 => Mode 1, W=RE R=FE (CLK inverted at each byte for
un unknown reason)
- CPOL=1 CPHA=0 => Mode 2, W=RE R=FE (CLK inverted at each byte for
un unknown reason)
- CPOL=1 CPHA=1 => Mode 3, W=FE R=RE
Regards,
Stany
On Fri, Feb 18, 2011 at 3:49 PM, stefan harjes <stefanharjes@xxxxxxxx> wrote:
> Hi,
>
> I am evaluating the FT4232H chip on the FT4232H Mini Module using libftdi.
>
> As described in the FTDI application note AN_114 and many other sources, there
> are four SPI modes defined (four combinations of the two bits cpol and cpha).
>
> In the description of the MPSSE engine (AN2232-01 - Command Proc....) there
> are only two SPI long (MSB) writes described (0x10 & 0x11 on page 7/8).
> However, from my understanding there should be four modes (two for each
> polarity). To make things worse, the combination which I appear to need
> cpol=0, cpha=1 (=SPI mode 1) seems to be missing.
>
> To make things appear even foolish, page 15/16 of AN2232-01 describes two SPI
> modes, which from my understanding do not exist (for example 0x30: out on
> positive edge, in on positive edge).
>
> When I use a scope, no matter which write/read command I issue to the MPSSE
> engine, I have not been able to get the SPI mode 1 (initial clock polarity 0,
> data out on rising edge).
>
> Any hints would be appreciated, as I am out of ideas right now...
> this likely renders the chip useless for my
> application.
>
> Best
>
> Stefan
>
>
>
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