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FPGA Interfacing ADC AD9480 Verilog


Working environmnet: 1. Intel FPGA DE2-115 with Cyclone IV 

                                    2. AD9480 LVDS customer board (Designed in 2004 Rev. B)   

                                    3. Power &Signal Generator & Measuring tool: Analog Device ADALM2000

Connections: 1. Assign FPGA 50MHz clock to SMA out and connected with ADC clock input

                      2. DRVDD, AVDD, VCTRL all have 3.3V input power. (Power is supplied by ADALM2000 module)

                      3. ADC board's Analogue input comes from ADALM2000 Signal Generator - Sine wave 2V peak to peak

                      4. Only connected ADC 8 bits output (D0T-D7T) to FPGA GPIO pins (D0C-D8C are for 2's complement outputs. The rest of pins are not neccessary for the 8 bits output, right?)


Some experiment results:

1. I assign the LEDs to GPIO pins on the FPGA board, so any digital signal changes happen on GPIO pins will be indicated by LEDs' states. (The default state is ON)

2. However, the LEDs always remain OFF state when I connect the FPGA to the AD9480 evaluation board, no matter how I change the Signal Generator's output. Or I should say no results was shown on the FPGA board.

3. Connecting the FPGA board with ADALM2000 module directly, the GPIO pins can read the digital signals properly no matter how I change the bits squence.

4. The AD9480 board can go SLEEP state if I connect the jumper.

5. I can't feel any heat from the ADC chip, even I power the board for a long time.

6. In the current situation, I only have the 50MHz clock from the FPGA board as the synchronous clock. Nor sure if this freq. will work for this board. (Clock voltage is 1.8V, can be up to 3.3V) 

7. Double check the power side doesn't have any issues. ADALM2000 supplies the power to the ADC. Only connected DRVDD, AVDD, VCTRL and three GNDs (One for each) 

8. Jump wires are used for SMA connection since I don't have SMA cable at the moment.(Inside pin is positive and outside ring is negative) The connections are kindly reliable. And the oscilloscope can detect the 50MHz signal. (but the ADALM2000 module cannot capture such a high freq. signal stably. I can see the signal, but it vibrates a lot.)


Last thing, appreciate anyone who can seend me some previous Verilog code examples on FPGA interfacing ADC. 

Best Regards!

  • For the ADC putputs, it should be affected by some noise if I loose the cables a little bit.  Most likely the evaluation board wasn't running at all. I tried to connect the GPIO pins to other pins on ADC board (e.g. 2's complement ones rather than true value pins) . All the outputs from the ADC will turn off the LEDs which means states are Zero.