Motorola MVME172 - Manual (Page 316)

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:
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 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