t15
AEN
t16
t2
t3
FDRQ,
PDRQ
t1
t4
FDACKX
PDACKX
t12
t14
t11
t6
t5
nIOR
or
t8
nIOW
t10
t9
t7
DATA
(DO-D7)
DATA VALID
t13
TC
NOTE: FDRQ refers to the DRQ assigned to the Floppy Disk
PDRQ refers to the DRQ assigned to the Parall el Port
FDACKX refers to the DRQ assi gned to the to the Floppy Disk
PDACKX refers to the DRQ assigned to the Parallel Port
Parameter
min
typ
max
units
0
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
t1
t2
t3
t4
t5
t6
t7
t8
t9
nDACK Delay Time from FDRQ High
DRQ Reset Delay from nIOR or nIOW
FDRQ Reset Delayfrom nDACK Low
nDACK Width
100
100
150
0
0
nIOR Delay from FDRQ High
nIOW Delay from FDRQ High
Data Access Time from nIOR Low
Data Set Up Time to nIOW High
Data to Float Delay from nIOR High
100
60
40
10
10
5
10
60
40
10
t10 Data Hold Timefrom nIOW High
t11
t12
t13 TC Pulse Width
t14 AEN SetUp to nIOR/nIOW
t15 AEN Hold from nDACK
nDACK Set Up to nIOW/nIOR Low
nDACK Hold After nIOW/nIOR High
100
TCActive to PDRQ Inactive
t16
FIGURE 5 - DMA TIMING
141
SMSC [ SMSC CORPORATION ]
