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AD9954 Eval board interfacing with a microprocessor

Question asked by ronaldo.nunez on Aug 17, 2012
Latest reply on Aug 21, 2012 by DSB

Hey Community

 

We are trying to communicate our AD9954 eval-board with a Atmel UC3 device using SPI (configured as master), but we can't see any waveform at output. We performed the following steps:

 

1) Changed the W2 jumper to "Manual Data in";

2) Fed the VCC and DVDD_IO with 3.3V (to turn it compatible with our processor output voltage level);

3) Fed the DVDD and AVDD with 1.8V (following the advise on the board);

4) Grounded the U13 pins: CLKMODESEL_DUT1, PWRDOWNCTRL_DUT1, IO_SYNC_DUT1, OSK_DUT1, PS1_DUT1, PS0_DUT1 and RB_ENABLE;

5) Connected SDIO to MOSI (Master Output), SDO to MISO (Master Input), SCLK to SCLK of the processor and CS_DUT to the chip select line of the processor;

6) FUD_DUT1 and RESET_DUT1 was connected to two parallel GPIO lines;

7) Fed the REF_CLK_DUT1 (J3) with 10 MHz, 0 to 500mV clock generated by a signal generator.

 

We've try the simplest test, as discribed on the thread 36154 (http://ez.analog.com/message/36154#36154), wrote to the register 0x04 and the word 0x19999999, which means that we expect a 1MHz tone as output. As you can see on the attached picture, after sent the register, we sent the data in a MSB first scheme (Last byte first (0x19) and after the remaining bytes 0x99 on the sequence). We also have performed the IOUPDATE (GPIO1/UL line on the attached picture).

 

Can you see what is wrong with our setup?

 

Thanks in advance.

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