In article <ie2dnXh0v4F10LfRnZ2dnUVZ_vmdnZ2d@giganews.com>,
elliott.nelson@n_o_s_p_a_m.charter.net says...
> Did anyone ever resolve this issue. I am trying to write to a similir
> image sensor and not receiving the ACK. I am using a bit bang I2C
> implementation. I have reviewed the image sensor timings and I am well
> within spec.
Which timings have you checked? Video or I2C?
I would actually suggesting capturing your I2C communications on
a digital scope and checking what is happening and that your are sending
the right information.
Often these sorts of problems end up as
Incorrect bit pattern (address/data)
Incorrect waiting for bit times
incorrect or open connections
incorrect voltage levels used
incorrect I2C termination
incorrect oscillator on imager
Some other configuration on the imager missing/wrong
It is very, very rarely the device at fault, sometimes the documentation.
Did anyone ever resolve this issue. I am trying to write to a similir
image sensor and not receiving the ACK. I am using a bit bang I2C
implementation. I have reviewed the image sensor timings and I am well
within spec.
Thanks,
Elliott
---------------------------------------
Posted through http://www.EmbeddedRelated.com
Reply by Kcin●November 29, 20082008-11-29
I tried to feed 100KHz and 400KHz to SCL @ 48MHz master clock, but
still no ack bit.
I will try to lower SCL to 80KHz.
More, I am wondering if SCL depends on the master clock.
I read several specs and it seems that many of their cmos run with
this "2-wire serial interface". What is the trick really?
Thanks.
Kicn
On Nov 29, 9:51=A0am, jakiec...@gmail.com wrote:
> On Nov 28, 3:06=A0am, "srl100" <srl...@yahoo.com> wrote:
>
> > >On Nov 27, 2:48 pm, Bob <SkiBoy...@excite.com> wrote:
> > >It's a Micron's CMOS image sensor. The spec only describes both SCL
> > >and SDA should be pull up 3.3V with a 1.5k ohm resistors. No suggested
> > >clock rate of SCL.
>
> > According to the datasheet athttp://download.micron.com/pdf/datasheets/=
imaging/MT9T001_3100_DS.pdf
>
> > "The two-wire serial bus operation requires certain minimum master cloc=
k
> > cycles between transitions. These are specified in the following diagra=
ms
> > in master clock cycles."...
>
> > and then there are a bunch of timing diagrams to peruse.
>
> I am actually working on the same thing and can not get an acknowledge
> either.
>
> I am running from the LH a SCL of 100KHz and my PIXCLOCK (which is the
> master for the MT9T001) at ~ 2.5 MHz.
>
> For some reason I still cannot get an acknowledge bit on I2C.
>
> I checked the timing diagrams and a 2.5MHz clock should meet the
> minimum by far, but still nothing...
>
> Anybody got any ideas?
>
> --Daniel
Reply by ●November 28, 20082008-11-28
On Nov 28, 3:06=A0am, "srl100" <srl...@yahoo.com> wrote:
> >On Nov 27, 2:48 pm, Bob <SkiBoy...@excite.com> wrote:
> >It's a Micron's CMOS image sensor. The spec only describes both SCL
> >and SDA should be pull up 3.3V with a 1.5k ohm resistors. No suggested
> >clock rate of SCL.
>
> According to the datasheet athttp://download.micron.com/pdf/datasheets/im=
aging/MT9T001_3100_DS.pdf
>
> "The two-wire serial bus operation requires certain minimum master clock
> cycles between transitions. These are specified in the following diagrams
> in master clock cycles."...
>
> and then there are a bunch of timing diagrams to peruse.
I am actually working on the same thing and can not get an acknowledge
either.
I am running from the LH a SCL of 100KHz and my PIXCLOCK (which is the
master for the MT9T001) at ~ 2.5 MHz.
For some reason I still cannot get an acknowledge bit on I2C.
I checked the timing diagrams and a 2.5MHz clock should meet the
minimum by far, but still nothing...
Anybody got any ideas?
--Daniel
Reply by srl100●November 28, 20082008-11-28
>On Nov 27, 2:48 pm, Bob <SkiBoy...@excite.com> wrote:
>It's a Micron's CMOS image sensor. The spec only describes both SCL
>and SDA should be pull up 3.3V with a 1.5k ohm resistors. No suggested
>clock rate of SCL.
According to the datasheet at
http://download.micron.com/pdf/datasheets/imaging/MT9T001_3100_DS.pdf
"The two-wire serial bus operation requires certain minimum master clock
cycles between transitions. These are specified in the following diagrams
in master clock cycles."...
and then there are a bunch of timing diagrams to peruse.
Reply by Bob●November 28, 20082008-11-28
Kcin wrote:
> On Nov 27, 2:48 pm, Bob <SkiBoy...@excite.com> wrote:
>> Kcin wrote:
>>> Hi, I tried to look for similar topics in the archive but no luck.
>>> I have a cmos image sensor, and it has a "two-wire serial interface"
>>> to read/write its on-chip registers. I tried to treat it like a I2C
>>> protocol, and fed a 100KHz at SCL, and write an address byte at SDA,
>>> but cannot get the acknowledge bit.
>>> Is it about the values of pull-up resistors in SCL and SDA? Or the
>>> clocking frequency problem??
>>> Thanks.
>>> Kcin
>> yes.
>> Or it might be something else. What does the data sheet tell you?
>> ** Posted fromhttp://www.teranews.com**
>
> It's a Micron's CMOS image sensor. The spec only describes both SCL
> and SDA should be pull up 3.3V with a 1.5k ohm resistors. No suggested
> clock rate of SCL. It does not have any signs of the word "i2c" as
> well, it calls it "Two-Wire Serial Interface". What standard is it
> really?
>
> "Serial Bus Description
> Registers are written to and read from the MT9T001 through the two-
> wire serial interface bus. The MT9T001 is a two-wire serial interface
> slave and is controlled by the two-wire serial clock (SCLK), which is
> driven by the two-wire serial interface master. Data is transferred
> into and out through the MT9T001 through the two-wire serial interface
> data (SDATA)
> line. The SDATA line is pulled up to 3.3V off-chip by a 1.5K�
> resistor. Either the slave or master device can pull the SDATA line
> down--the two-wire serial interface protocol determines which device is
> allowed to pull the SDATA line down at any given time."
you need to get the full data sheet. Omnivision made us sign a NDA.
Micron (Aptina) might require it too. Contact Aptina or their
distributor if you have to.
Bob
** Posted from http://www.teranews.com **
Reply by Mike Harrison●November 27, 20082008-11-27
On Thu, 27 Nov 2008 06:56:21 -0800 (PST), Kcin <takit.lau@gmail.com> wrote:
>On Nov 27, 2:48 pm, Bob <SkiBoy...@excite.com> wrote:
>> Kcin wrote:
>> > Hi, I tried to look for similar topics in the archive but no luck.
>>
>> > I have a cmos image sensor, and it has a "two-wire serial interface"
>> > to read/write its on-chip registers. I tried to treat it like a I2C
>> > protocol, and fed a 100KHz at SCL, and write an address byte at SDA,
>> > but cannot get the acknowledge bit.
>>
>> > Is it about the values of pull-up resistors in SCL and SDA? Or the
>> > clocking frequency problem??
>>
>> > Thanks.
>>
>> > Kcin
>>
>> yes.
>> Or it might be something else. What does the data sheet tell you?
>> ** Posted fromhttp://www.teranews.com**
>
>It's a Micron's CMOS image sensor. The spec only describes both SCL
>and SDA should be pull up 3.3V with a 1.5k ohm resistors. No suggested
>clock rate of SCL. It does not have any signs of the word "i2c" as
>well, it calls it "Two-Wire Serial Interface". What standard is it
>really?
I2C interfaces often aren't called I2C, presumably due to possible licensing/patent issues or subtle
implementration differences. However the required waveforms will be in the datasheet.
Reply by Kcin●November 27, 20082008-11-27
On Nov 27, 2:48 pm, Bob <SkiBoy...@excite.com> wrote:
> Kcin wrote:
> > Hi, I tried to look for similar topics in the archive but no luck.
>
> > I have a cmos image sensor, and it has a "two-wire serial interface"
> > to read/write its on-chip registers. I tried to treat it like a I2C
> > protocol, and fed a 100KHz at SCL, and write an address byte at SDA,
> > but cannot get the acknowledge bit.
>
> > Is it about the values of pull-up resistors in SCL and SDA? Or the
> > clocking frequency problem??
>
> > Thanks.
>
> > Kcin
>
> yes.
> Or it might be something else. What does the data sheet tell you?
> ** Posted fromhttp://www.teranews.com**
It's a Micron's CMOS image sensor. The spec only describes both SCL
and SDA should be pull up 3.3V with a 1.5k ohm resistors. No suggested
clock rate of SCL. It does not have any signs of the word "i2c" as
well, it calls it "Two-Wire Serial Interface". What standard is it
really?
"Serial Bus Description
Registers are written to and read from the MT9T001 through the two-
wire serial interface bus. The MT9T001 is a two-wire serial interface
slave and is controlled by the two-wire serial clock (SCLK), which is
driven by the two-wire serial interface master. Data is transferred
into and out through the MT9T001 through the two-wire serial interface
data (SDATA)
line. The SDATA line is pulled up to 3.3V off-chip by a 1.5K=D9
resistor. Either the slave or master device can pull the SDATA line
down--the two-wire serial interface protocol determines which device is
allowed to pull the SDATA line down at any given time."
Reply by Bob●November 27, 20082008-11-27
Kcin wrote:
> Hi, I tried to look for similar topics in the archive but no luck.
>
> I have a cmos image sensor, and it has a "two-wire serial interface"
> to read/write its on-chip registers. I tried to treat it like a I2C
> protocol, and fed a 100KHz at SCL, and write an address byte at SDA,
> but cannot get the acknowledge bit.
>
> Is it about the values of pull-up resistors in SCL and SDA? Or the
> clocking frequency problem??
>
> Thanks.
>
> Kcin
yes.
Or it might be something else. What does the data sheet tell you?
** Posted from http://www.teranews.com **
Reply by Kcin●November 26, 20082008-11-26
Hi, I tried to look for similar topics in the archive but no luck.
I have a cmos image sensor, and it has a "two-wire serial interface"
to read/write its on-chip registers. I tried to treat it like a I2C
protocol, and fed a 100KHz at SCL, and write an address byte at SDA,
but cannot get the acknowledge bit.
Is it about the values of pull-up resistors in SCL and SDA? Or the
clocking frequency problem??
Thanks.
Kcin