DP8473N NSC [National Semiconductor], DP8473N Datasheet - Page 24

• Manufacturer Part Number: DP8473N
• Description: DP8473 Floppy Disk Controller PLUS-2
• Manufacturer: NSC [National Semiconductor]

AC Electrical Characteristics
OSC2 CLOCK AND RESET TIMING
DMA TIMING (Note 9)
Note 9 DMA Acknowledge is sufficient to acknowledge a data transfer Read or Write Strobes are neccessary only if data is to be presented to the data bus If
Read Write Strobes are applied then they and the Acnowledge must be removed within 1 s of each other
Note 10 TC is is the terminal count pin which terminates the data transfer operation There are several constraints placed on the timing of TC 1) TC is enabled by
DAK so TC must be pulsed while DAK is low 2) TC must occur before ((1 data rate x 8)
DRIVE READ TIMING
Symbol
t
t
t
t
t
t
AQ
QA
AA
QR
TT
TQ
Symbol
t
Symbol
t
t
t
RDW
H
L
RW
End of DRQ from DAK
DAK Assertion from DRQ
DAK Pulse Width
DRQ to Read or Write Strobe
TC Strobe Width
Time after Last DRQ That
TC Must Be Asserted By
Read Data Pulse Width
Clock High Time
Clock Low Time
Reset Pulse Width
Parameter
Parameter
Parameter
(Continued)
24
Min
100
16
16
b
Min
Min
25
10
75
10
50
1 s) Data rate is the exact data transfer rate being used
TL F 9384 – 15
(Note 10)
Max
TL F 9384 – 13
Max
Max
115
TL F 9384 – 14
Units
Units
ns
ns
ns
Units
ns
ns
ns
ns
ns
ns
ns