Other Parts Discussed in Thread: TXV0108, TXV0106
Tool/software:
We are currently using your level shifter PN SN74AXCH8T245PWR wired similar to what is shown in your app note Scea065B, Section 2.5.1 with level shifters from +3.3V (RGMII MPU Side) and 1.8V (Ethernet switch PHY Side) but are not able to establish a handshake between the MPU RGMII MAC interface and the Ethernet switch RGMII PHY interface and obtain a working Ethernet connection.
We see RGMII transmit data through the level shifter (+3V3 to 1V8 translation) from the MPU side but the signal looks attenuated with the +1V8 closer to 1V.
We are not seeing the RGMII receive data from the Ethernet switch on either side of the level shifter.
We currently have series (1K, 220) and pull-down (49.9) impedance matching resistors installed on the RGMII data and control lines to help with signal integrity and prevent reflections.
Questions:
Are your level shifters SN74AXCH8T245PWR fast enough to support an RGMII interface configured for 1GBs Ethernet speeds?
Would the series and pull-down impedance matching resistors cause any issues?
Any other recommendations or hardware recommendations that may help fix this issue?
