Why do I see the following message when attempting to start Transceiver Toolkit (TTK) in Quartus Prime software version 16.0? com.altera.debug.core SEVERE: TTK failed reading from PHY slave_<slave address> - Why do I see the following message when attempting to start Transceiver Toolkit (TTK) in Quartus Prime software version 16.0? com.altera.debug.core SEVERE: TTK failed reading from PHY slave_<slave address> Description Due to a problem in the Quartus® Prime version 16.0 software, you may see any of the messages below when you start Transceiver ToolKit (TTK) for a non-PCIe ® interface but have a PCIe interface in your design. You may also see these messages when you start TTK for a PCIe interface. You may also see errors in the System Console tree as shown in this screenshot . This is due to missing clock connections for the Hard IP for PCI Express® IP core's Transceiver Reconfiguration Controller, which impacts the use of TTK for other interfaces. com.altera.debug.core SEVERE: TTK failed reading from PHY slave_, cannot enable TTK functionality for this PHY. Please verify the reconfig_clk is running and ensure this PHY is not stuck in reset. com.altera.debug.core SEVERE: open_service: Could not open service at /devices/)|..@1#USB-1#<....>/master: Channel busy error: open_service: Could not open service at /devices/)|..@1#USB-1#<...>/master: Channel busy while executing "open_service master $" (procedure "" line 6) invoked from within "" (file "" line ) invoked from within "" Resolution To work around this issue, edit the instantiation of the Hard IP for PCI Express® core and add the PCIe reference clock to the Transceiver Reconfiguration Controller connections as shown below. Replace <refclk_clk> below with the actual PCIe refclk signal used in your design. FROM: .xcvr_reconfig_clk (1'b0), ... .reconfig_pll0_clk (1'b0), ... .reconfig_pll1_clk (1'b0), TO: .xcvr_reconfig_clk (<refclk_clk>), ... .reconfig_pll0_clk (<refclk_clk>), ... .reconfig_pll1_clk (<refclk_clk>), This problem is scheduled to be fixed in a future version of the Quartus® Prime software. Related Articles Why does Arria 10 Transceiver Toolkit (TTK) fail to find any PCIe transceiver links in Quartus Prime software 16.0? Custom Fields values: ['novalue'] Troubleshooting 0 False ['novalue'] ['FPGA Dev Tools Quartus® Prime Software Pro'] novalue 16.0 ['Programmable Logic Devices'] ['novalue'] ['novalue'] ['novalue']