
PIC17C4X
DS30412C-page 162
1996 Microchip Technology Inc.
Applicable Devices 42 R42 42A 43 R43 44
FIGURE 17-12: MEMORY INTERFACE READ TIMING
TABLE 17-12: MEMORY INTERFACE READ REQUIREMENTS
Parameter
No.
Sym
Characteristic
Min
Typ
Max
Units Conditions
150
TadV2alL
AD<15:0> (address) valid to ALE
↓
(address setup time)
0.25Tcy - 30
—
ns
151
TalL2adI
ALE
↓ to address out invalid
(address hold time)
5*
—
ns
160
TadZ2oeL
AD<15:0> high impedance to OE
↓
0*
—
ns
161
ToeH2adD
OE
↑ to AD<15:0> driven
0.25Tcy - 15
—
ns
162
TadV2oeH
Data in valid before OE
↑
(data setup time)
35
—
ns
163
ToeH2adI
OE
↑to data in invalid (data hold time)
0
—
ns
164
TalH
ALE pulse width
—
0.25TCY §
—
ns
165
ToeL
OE pulse width
0.5Tcy - 35 §
—
ns
166
TalH2alH
ALE
↑ to ALE↑ (cycle time)
—
TCY §
—
ns
167
Tacc
Address access time
—
0.75 TCY-40
ns
168
Toe
Output enable access time
(OE low to Data Valid)
—
0.5 TCY - 60
ns
*
These parameters are characterized but not tested.
Data in “Typ” column is at 5V, 25
°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
§
This specication guaranteed by design.
OSC1
ALE
OE
AD<15:0>
WR
Q1
Q2
Q3
Data in
Addr out
150
151
160
166
165
163
161
'1'
Q4
Q1
Q2
Addr out
164
168
167
162