Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 11/27/2024
Public
Document Table of Contents

5.5.6.5.2. Output Enable Signal Generation

When the PHY is configured in NAND mode, each of the data pins (DQ pins) and the DQS pin requires an output enable (OE) control signal that must be set in the appropriate time, so the signals to transmit are correctly reflected in the pins. The OE signals are generated from the dfi_wrdata_en_p0/p1 and dfi_wrdqs_en_p0_p1 NAND memory controller signals (these signals are converted into dfi_wrdata_en and dfi_wrdqs_en in the frequency ratio module). The time in which the rising and falling edge of these signals occurs is controlled by the phy_dq_timing_reg register (data_select_oe_start and data_select_oe_end fields for DQ pins) and the phy_dqs_timing_reg register (for the dqs_select_oe_start and dqs_select_oe_end fields for the DQS pin). A lower value implies that the rising or falling edge of the OE signal occurs earlier while a higher value implies that the falling edge occurs later. The setting of the OE signal is controlled by *start fields and the clearing is controlled by the *end fields. Each step has a resolution of ½ clk_phy clock cycle. The OE signal is fanned out to all DQ pins and one DQS pin.

Figure 164. Generation of Output Enable (OE) Signal in Write Data Path