anyone used the AD5301 DAC?

[starfire]

Has anyone used the Analog Devices AD5301 DAC? I'm trying to use it to
output a variable voltage based on an operator selection but can't get
anything out of the DAC.

I have confirmed the correct command sequence going into the chip with a
logic analyzer. In sending a 0x55 byte, I have confirmed the bytes going to
the chip are 0x18, 0x25, and 0x50 (in that order). The output remains
absolutely flatline. I am just monitoring the output with a scope and no
other load.

I saw no mention in the datasheet for an init sequence. The chip is sending
the ack bits back to the micro when the command sequence is sent. It
appears the communication between the micro and the chip is valid... just no
output...

Does anyone have any experience with this chip? Any help appreciated.

Thanks.

Dave

 

[Ben Jackson]

On 2008-07-15, starfire <starfire151@cableone.net> wrote:

Has anyone used the Analog Devices AD5301 DAC?

I was almost sure I had, but what I used was the AD5300 (SPI interface).

I have confirmed the correct command sequence going into the chip with a
logic analyzer. In sending a 0x55 byte, I have confirmed the bytes going to
the chip are 0x18, 0x25, and 0x50 (in that order). The output remains

Well, the 2 in 0x25 is setting 100k impedance powerdown mode. You should
see 0x18 (address + write) 0x05 0x50. The upper nybble of the first data
word needs to be 0. 1, 2 and 3 would all be powerdown modes.

--
Ben Jackson AD7GD
<ben@ben.com>
http://www.ben.com/

 

[starfire]

"Ben Jackson" <ben@ben.com> wrote in message
news:slrng7q01g.1765.ben@saturn.home.ben.com...

On 2008-07-15, starfire <starfire151@cableone.net> wrote:
Has anyone used the Analog Devices AD5301 DAC?

I was almost sure I had, but what I used was the AD5300 (SPI interface).

I have confirmed the correct command sequence going into the chip with a
logic analyzer. In sending a 0x55 byte, I have confirmed the bytes going
to
the chip are 0x18, 0x25, and 0x50 (in that order). The output remains

Well, the 2 in 0x25 is setting 100k impedance powerdown mode. You should
see 0x18 (address + write) 0x05 0x50. The upper nybble of the first data
word needs to be 0. 1, 2 and 3 would all be powerdown modes.

--
Ben Jackson AD7GD
ben@ben.com
http://www.ben.com/

Hi Ben -

Why does it always seem so obvious in hindsight?

I read that section in the datasheet and, for some reason, I thought that
was the impedance presented to the system when the chip was powered down. I
see now that its the impedance presented to the system when the chip is
disabled, not powered down.

Thanks very much for that catch! It works fine now.

Dave