Altera External Memory PHY Interface - Manual (Page 56)

3–40 Chapter 3: Functional Description—ALTMEMPHY (nonAFI)
Additional Debug Signals
External Memory PHY Interface (ALTMEMPHY) (nonAFI) Megafunction User Guide © January 2010 Altera Corporation
■ pll_reconfig_busy
■ pll_reconfig_clk
■ pll_reconfig_data_out
■ pll_reconfig_reset
1 For full description of the signals listed and their required operation, refer to the
respective Device Handbooks or
Phase-Locked Loop Reconfiguration
(ALTPLL_RECONFIG) Megafunction User Guide .
1 The output clock order is fixed in the ALTMEMPHY (seq_pll_select) and a
mapping takes place to align with the required clock port used for each different
device family. Refer to _phy_alt_mem_phy.v(hd) file and refer to the
section that starts with the following code:
// NB This lookup table shall be different for CIII/SIII
// The PLL phasecounterselect is 3 bits wide, therefore hardcode the
output to 3 bits:
Calibration Status Interface
The following calibration signals provide information for ALTMEMPHY
megafunction:
■ ctl_cal_success indicates calibration success
■ ctl_cal_fail indicates calibration failure
Additional Calibration Status Interface Signals
Add the signals in Table 3–17 to your simulation to provide additional information
about calibration status:
Table 3–17. Signals for Calibration Status
Signal Description
rsu_codvw_phase
(Center of data valid window)
The ALTMEMPHY resynchronization setup unit (RSU) sweeps the phase of a
resynchronization clock across 360° (full-rate mode) or 720° (half-rate
mode) of a memory clock cycle. Data reads from the DIMM are performed
for each phase position, and a data valid window is located, which is the set
of resynchronization clock phase positions where data is successfully read.
The final resynchronization clock phase is set at the center of this range: the
center of the data valid window or CODVW. This output is set to the current
calculated value for the CODVW, and represents how many phase steps
were performed by the PLL to offset the resynchronization clock from the
memory clock.
rsu_read_latency
(Read latency at the center of the window)
If the RSU can find one data valid window (and not more than one) then the
resynchronization clock is positioned at the center and the
rsu_read_latency
output is then set to the read latency (in phy_clk
cycles) using that resynchronization clock phase. If calibration is
unsuccessful then this signal remains at 0.
rsu_no_dvw_err
(Calibration failed due to no window found)
If the RSU sweeps the resynchronization clock across every phase and does
not see any valid data at any phase position, then calibration fails and this
output is set to 1.