Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 4/01/2024
Public
Document Table of Contents

5.5.7.3. DLL Secondary Delay Configuration

Depending on the DLL operation mode, the values written in the phy_dll_slave_ctrl_reg register will have a different meaning in terms of time delay calculation as described below.

Table 231.  DLL Secondary Delay Operation Mode Values
DLL Operation mode Lock Mode Total Delay Notes
Bypass mode N/A DLLDly * (reg_value+1) N/A
Normal operation Full clock mode Tclk_phy*(reg_value+1)/256 Delay was a resolution of 1/256 of clock period.

Half clock mode

Tclk_phy*(reg_value+1)/256

reg_value must be lower than 128. This means that the maximum delay is equal to half clock cycle.
Saturation mode DLLDly * (reg_value+1) Same as bypass mode. This case is typical for low values of PHY clock frequency.
Where:
  • DLLDly: Delay of a single delay element.
  • reg_val: 8-bit value stored in read_dqs_delay, read_dqs_cmd_delay, clk_wr_delay or clk_wrdqs_delay.
  • Tclk_phy: Period of PHY clock.