AD9911 DDS frequency synthesizer

[PC]

Hi All,

I have been struggling with the Analog Devices chip AD9911 for over a
week and still no luck.
The SPI Clk and Data are perfect, all the analog and digital voltages
are set as specified in the data sheet. Here are some of my register
values

CSR - 0x"22"
FR1 - 0x"1800"
FR2 - 0x"0000"
CFR - 0x"000382"
CTW0 - 0x"9810624D"
CPOW0 - 0x"0000"

My target is to generate an ouput frequency of 74.25Mhz with a 25 Mhz
system clock. Am I overlooking something obvious, have you faced
similar issues with this chip. Any help in resolving the problem are
welcome.

Regards
PC

 

[Spehro Pefhany]

Hi All,

I have been struggling with the Analog Devices chip AD9911 for over a
week and still no luck.
The SPI Clk and Data are perfect, all the analog and digital voltages
are set as specified in the data sheet. Here are some of my register
values

CSR - 0x"22"
FR1 - 0x"1800"
FR2 - 0x"0000"
CFR - 0x"000382"
CTW0 - 0x"9810624D"
CPOW0 - 0x"0000"

My target is to generate an ouput frequency of 74.25Mhz with a 25 Mhz
system clock. Am I overlooking something obvious, have you faced
similar issues with this chip. Any help in resolving the problem are
welcome.

Regards
PC

Have not used that particular chip, but I suspect something to do with
the SPI-- data/clock phase-- there are 4 possibilities, number of
bits, total number of clocks, or format (MSB first is default, right?)


Best regards,
Spehro Pefhany

 

[[email protected]]

Hi All,

I have been struggling with the Analog Devices chip AD9911 for over a
week and still no luck.
The SPI Clk and Data are perfect, all the analog and digital voltages
are set as specified in the data sheet. Here are some of my register
values

CSR - 0x"22"
FR1 - 0x"1800"
FR2 - 0x"0000"
CFR - 0x"000382"
CTW0 - 0x"9810624D"
CPOW0 - 0x"0000"

My target is to generate an ouput frequency of 74.25Mhz with a 25 Mhz
system clock. Am I overlooking something obvious, have you faced
similar issues with this chip. Any help in resolving the problem are
welcome.

Regards
PC

What problem? You didn't mention any details. Wrong frequency?
Amplitude? Shape? No output at all? Chip overheating? What?

 

[PC]

What problem? You didn't mention any details. Wrong frequency?
Amplitude? Shape? No output at all? Chip overheating? What?

I Don't get any output at all, although I get a sync_clk output ( 25 /
4) . The chip is configured in the single bit 3 wire mode, the SPI
read is also unsucessful. The data sheet doesn't say much about SPI
programming though.

 

[[email protected]]

I Don't get any output at all, although I get a sync_clk output ( 25 /
4) . The chip is configured in the single bit 3 wire mode, the SPI
read is also unsucessful. The data sheet doesn't say much about SPI
programming though.

It's a current-mode DAC. You do have a current to voltage converter at
the output?

 

[[email protected]]

I Don't get any output at all, although I get a sync_clk output ( 25 /
4) . The chip is configured in the single bit 3 wire mode, the SPI
read is also unsucessful. The data sheet doesn't say much about SPI
programming though.

if spi reads don't work, there's a very good chance spi writes don't
work either
so chase that first

-Lasse

 

[Rene Tschaggelar]

Any test outputs ? How about testpattern.
Incremental approaches ?

Rene