dp8421a National Semiconductor Corporation, dp8421a Datasheet - Page 40

• Manufacturer Part Number: dp8421a
• Description: Microcmos Programmable 256k/1m/4m Dynamic Ram Controller/drivers
• Manufacturer: National Semiconductor Corporation

10 0 Dual Accessing (DP8422A)
10 3 2 LOCK Input
When the LOCK input is asserted the currently granted port
can ‘‘lock out’’ the other port through the insertion of wait
states to that port’s access cycle LOCK does not disable
FIGURE 34b Wait States during a Port B Access
FIGURE 35 LOCK Function
(Continued)
40
refreshes it only keeps GRANTB in the same state even if
the other port requests an access as shown in Figure 35a
LOCK can be used by either port
TL F 8588 – E8
TL F 8588 – 29