Motorola MVME172 用户手册
5-26
Computer Group Literature Center Web Site
MCECC
5
STON2-STON0
STON2-STON0 control the amount of time that the
scrubber occupies the DRAM before providing a window
during which the local bus and refresher might use it.
They control the on time as follows:
scrubber occupies the DRAM before providing a window
during which the local bus and refresher might use it.
They control the on time as follows:
STOFF2 STOFF1 STOFF0 Scrubber Time Off
0
0
0
Request DRAM immediately
0
0
1
Request DRAM after 16 BCLK
cycles
cycles
0
1
0
Request DRAM after 32 BCLK
cycles
cycles
0
1
1
Request DRAM after 64 BCLK
cycles
cycles
1
0
0
Request DRAM after 128 BCLK
cycles
cycles
1
0
1
Request DRAM after 256 BCLK
cycles
cycles
1
1
0
Request DRAM after 512 BCLK
cycles
cycles
1
1
1
Request DRAM never
STON2
STON1
STON0
Scrubber Time On
0
0
0
Keep DRAM for 1 memory cycle
0
0
1
Keep DRAM for 16 BCLK
cycles
cycles
0
1
0
Keep DRAM for 32 BCLK
cycles
cycles
0
1
1
Keep DRAM for 64 BCLK
cycles
cycles
1
0
0
Keep DRAM for 128 BCLK
cycles
cycles
1
0
1
Keep DRAM for 256 BCLK
cycles
cycles
1
1
0
Keep DRAM for 512 BCLK
cycles
cycles
1
1
1
Keep DRAM for TOTAL
SCRUB TIME
SCRUB TIME