Part Number: ADS54J66 Hello, Here is what I'm trying to do: Interface the ADS54J66EVM board directly with a Xilinx KX705 FPGA board, without using any interposer card in the middle. Essentially, I want to be able to set up the data interface (the JESD lanes, etc) as well as the control interface (SPI, for register read/write). The reason for writing this post is I'm having difficulty with getting the FPGA to read/write the register values on the LMK04828 chip that is present on the ADS54J66EVM board. Here is how I have set it up: I've implemented the SPI interface on the FPGA, and this has been tested in simulation. The FPGA essentially writes a register value, and then attempts to read this register value back. The serial interface is routed as follows, in accordance with the ADS54J66EVM schematic. The CS* signal from the FPGA is routed to pin G15 on the FMC connector The SCK signal from the FPGA is routed to pin C14 on the FMC connector The SDIO signal to/from the FPGA is routed to pin C15 on the FMC connector The I/O standard for these signals is LVCMOS25 (is this the correct value to use?) The SPI clock frequency is 1.5625 MHz All the setup and hold constrains are easily satisfied The tri-state logic on the SDIO pin has been implemented correctly, and validated using simulation JP3 on the ADS54J66EVM is in the "FMC" location. The USB port is unconnected, but the power supply is connected on the ADS54J66 board I've verified that all the test-points on the board are receiving the correct voltage I first write a register, and then attempt to read it back to make sure that the correct value has been read. Unfortunately, in the read phase, I get only 0s on the SDIO pin. Does anyone have any pointers of what I might be doing wrong? Does the Altera chip on the ADS54J66 EVM board need to be programmed at all? Or is simply setting the jumper JP3 to "FMC" sufficient, and then I can simply ignore the Altera chip and the USB port? Finally, has anyone else been able to get this to work? I also found this link (below), but the example provided there was in LabVIEW. Thank you -- your help will be greatly appreciated!
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