Motorola MVME172 manual STON2-STON0, Scrubber Time Off, Scrubber Time On

5

MCECC

STOFF2	STOFF1	STOFF0	Scrubber Time Off
0	0	0	Request DRAM immediately
0	0	1	Request DRAM after 16 BCLK
			cycles
0	1	0	Request DRAM after 32 BCLK
			cycles
0	1	1	Request DRAM after 64 BCLK
			cycles
1	0	0	Request DRAM after 128 BCLK
			cycles
1	0	1	Request DRAM after 256 BCLK
			cycles
1	1	0	Request DRAM after 512 BCLK
			cycles
1	1	1	Request DRAM never

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:

STON2	STON1	STON0	Scrubber Time On
0	0	0	Keep DRAM for 1 memory cycle
0	0	1	Keep DRAM for 16 BCLK
			cycles
0	1	0	Keep DRAM for 32 BCLK
			cycles
0	1	1	Keep DRAM for 64 BCLK
			cycles
1	0	0	Keep DRAM for 128 BCLK
			cycles
1	0	1	Keep DRAM for 256 BCLK
			cycles
1	1	0	Keep DRAM for 512 BCLK
			cycles
1	1	1	Keep DRAM for TOTAL
			SCRUB TIME

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