MDDR Subsystem
Microsemi Proprietary UG0446 User Guide Revision 7.0
84
[3:0]
REG_DDRC_REFRESH_MARGIN
0×02
Threshold value in number of clock cycles
before the critical refresh or page timer expires.
A critical refresh is to be issued before this
threshold is reached. Microsemi recommends
using the default value.
Unit: Multiples of 32 clocks.
Table 64 •
DDRC_ZQ_SHORT_INT_REFRESH_MARGIN_2_CR
Bit
Number Name
Reset
Value Description
[31:8]
Reserved
0×0
Software should not rely on the value of a
reserved bit. To provide compatibility with
future products, the value of a reserved bit
should be preserved across a read-modify-
write operation.
[7:0]
REG_DDRC_T_ZQ_SHORT_INTERVAL_X1024
0×0
20 bits are split into two registers.
[19:12] bits of
REG_DDRC_T_ZQ_SHORT_INTERVAL_X10
24.
Average interval to wait between automatically
issuing ZQ calibration short (ZQCS)
commands to DDR3 devices. Not considered if
REG_DDRC_DIS_AUTO_ZQ = 1.
Units: 1,024 clock cycles
This is only present for implementations
supporting DDR3 devices.
Table 65 •
DDRC_PERF_PARAM_1_CR
Bit
Number Name
Rese
t
Valu
e
Description
[31:16]
Reserved
0×0
Software should not rely on the value of a reserved bit. To
provide compatibility with future products, the value of a
reserved bit should be preserved across a read-modify-write
operation.
Table 63 •
DDRC_ZQ_SHORT_INT_REFRESH_MARGIN_1_CR
(continued)