Category: Hardware
Product Number: AD9174
I'm trying to configure an AD9174 Evaluation Board entirely through SPI (using Arduino Mega 2560). My goal is to configure the device only by writing the required registers over SPI.
I want to:
- Bypass the internal DAC PLL.
- Apply an external clock to J34 (CLKIN).
- Operate the AD9174 in NCO-only mode (no JESD204 link).
- Generate a 10 MHz sine wave using the internal Main NCO
Hardware Setup
- Board: AD9174 Evaluation Board
- External clock applied to J34 (CLKIN)
- Clock frequency: 3 GHz
- JESD204 link is not connected.
To bypass the PLL, I programmed:
0x095 = 0x01 // PLL bypass
0x790 = 0xFF // Power down PLL
0x791 = 0x1F // Power down PLLI then configured the Main NCO by:
- Enabling the Main NCO
- Programming the FTW for a 10 MHz output
- Triggering the FTW update
- Enabling NCO-only mode
- Programming the DC amplitude registers, as given in table 57 of the AD9174 datasheet
SPI communication appears to be working correctly because I can successfully read back all written register values.
Problem
The DLL never locks, and I do not observe any DAC output.
Questions
- Besides Register 0x095, are there any additional registers that must be configured when using an external clock directly?
- Is there a required initialization sequence for PLL bypass mode that differs from the normal startup sequence?
Please help me resolve this issue.
