17.5.8.2.5 Constraints on refresh_timerX_start_value_x32

The refresh_timerX_start_value_x32 register fields control the relative timing of refreshes to different ranks.

The register fields must obey the following constraint:

refresh_timerX_start_value_x32 + RoundUp(RFSHTMG.t_rfc_min/32) < RFSHTMG.t_rfc_nom_x1_x32

If RFSHTMG.t_rfc_nom_x1_sel is set, RoundDown(RFSHTMG.t_rfc_nom_x1_x32/32) should be used in the above constraint.

Also, note that the register field refresh_timerX_start_value_x32 cannot be changed after initialization. So the value of the register RFSHTMG.t_rfc_nom_x1_x32 used above should be anticipated as the minimum value which will be used, considering frequency change, fine granularity refresh, etc.

For LPDDR2/3, if DERATEEN.derate_enable =1, use minimum RFSHTMG.t_rfc_nom_x1_x32/4 as value in calculation of refresh_timerX_star_value_x32 to consider possible effect of derating in high temperature case.