DP8421AV-25 National Semiconductor, DP8421AV-25 Datasheet - Page 40

• Manufacturer Part Number: DP8421AV-25
• Description: IC CTRLR/DVR CMOS PROGRAM 68PLCC
• Manufacturer: National Semiconductor

Specifications of DP8421AV-25

• Controller Type: Dynamic RAM (DRAM)
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 68-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *DP8421AV-25

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