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TMP92CZ26A
92CZ26A-231
(6) Refresh control
The TMP92CZ26A supports two kinds of refresh commands: Auto Refresh and Self Refresh.
(a) Auto Refresh
When SDRCR<SRC> is set to “1”, the Auto Refresh command is automatically issued at
intervals specified by SDRCR<SRS2:0>. The Auto Refresh interval can be specified in a
range of 47 states to 1248 states (0.78 μs to 20.8 μs at f
SYS
= 60 MHz).
The CPU operation (instruction fetch and execution) is halted while the Auto Refresh
command is being executed.
Figure3.10.6 shows the Auto Refresh cycle timing, and
Table3.10.3 shows the Auto Refresh interval settings. The Auto Refresh function cannot be
used in IDLE1 and STOP modes. In these modes, use the Self Refresh function to be
explained next.
Note: A system reset disables the Auto Refresh function.
Figure3.10.6
Auto Refresh Cycle Timing
Table3.10.3 Auto Refresh Intervals
Unit [μs]
SDRCR<SRS2:0> Frequency (System Clock)
SRS2 SRS1 SRS0
Auto
Refresh
Interval
(states)
6 MHz 10 MHz 20 MHz 40 MHz 60 MHz 80 MHz
0 0 0 47 7.8 4.7 2.4 1.18 0.78 0.59
0 0 1 78 13.0 7.8 3.9 1.95 1.30 0.98
0 1 0 156 26.0 15.6 7.8 3.90 2.60 1.95
0 1 1 312 52.0 31.2 15.6 7.80 5.20 3.90
1 0 0 468 78.0 46.8 23.4 11.70 7.80 5.85
1 0 1 624 104.0 62.4 31.2 15.60 10.40 7.80
1 1 0 936 156.0 93.6 46.8 23.40 15.60 11.70
1 1 1 1248 208.0 124.8 62.4 31.20 20.80 15.60
SDCLK
SDCKE
SDLUDQM
SDLLDQM
Auto Refresh
2states
SDCS
SDRAS
SDCAS
SDWE