com20020-5 Standard Microsystems Corp., com20020-5 Datasheet - Page 48

• Manufacturer Part Number: com20020-5
• Description: Com20020-5 Ulanc Universal Local Area Network Controller With 2k X 8 On-board Ram
• Manufacturer: Standard Microsystems Corp.

FIGURE 12 - NON-MULTIPLEXED BUS, 80XX-LIKE CONTROL SIGNALS; READ CYCLE
A0-A2
D0-D7
nCS
nRD
*
**
Note 1:
will now be 45nS measured from the leading edge of nCS.
nCS may become active after control becomes active, but the access time
t1
t2
t3
t4
t5
t6
t7
T is the Arbitration Clock Period.
T is identical to XTAL1 if SLOW ARB = 0,
T is twice XTAL1 period if SLOW ARB = 1
The Microcontroller typically accesses the COM20020-5 on every other cycle.
Therefore, the cycle time specified in the microcontroller's datasheet
should be doubled when considering back-to-back COM20020-5 cycles.
Address Setup to nRD Active
Address Hold from nRD Inactive
nCS Setup to nRD Active
nCS Hold from nRD Inactive
Cycle Time (nRD Low to Next Time Low)
nRD High to Data High Impedance
nRD Low to Valid Data
t1
t3
Parameter
t6
48
VALID
VALID DATA
t5
min
4T*
15
10
5**
0
0
max
40
20
t7
t2
t4
units
nS
nS
nS
nS
nS
nS
nS