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Question asked by Otto_ottO on Aug 3, 2018
Latest reply on Aug 10, 2018 by larsc

Having a little trouble getting the SPI interface working on the AD9144-FMC-EBZ (13045 Rev B) board. The board is connected to a Xilinx KCU105 via the FMC HPC connector. Oddly, I'm seeing a ~76MHz signal clock on the SPI. It's pretty far from square. I'm using a Xilinx AXI Quad Spi core with ext_spi_clk input of 100MHz and frequency divider of 64 which should yield an on the wire SPI clock of  1.5625MHz.


I've driven the FMC_SPI_EN line (P1.D12) high following the inference on the schematics- "FMC_SPI_EN WILL NEED TO BE SAMPLED AS ANALOG, SINCE IT MAY BE AS LOW AS 1.2v LOGIC HIGH"    which appears next to the onboard PIC micro. On the KCU105 this connection traces back to Bank 66 pin K13 which is running at 1.8V.


Nothing is connected to USB port.


The I2C interface works although produces what looks like non-compliant FRU info, and the board is receiving VADJ at 1.8V.


I can't get the SPI interface to return anything other than 0x00. Any thing special about using this particular board as an FMC board? Any ideas?