am79c30a Advanced Micro Devices, am79c30a Datasheet - Page 80

• Manufacturer Part Number: am79c30a
• Description: Digital Subscriber Controller ?dsc ?circuit
• Manufacturer: Advanced Micro Devices

Microprocessor Read/Write Timing
Microprocessor Read Timing
Microprocessor Write Timing
Notes:
1. The read/write recovery time of 200 ns holds in all cases except when a write command register operation is followed by a
2. Successive reads of the D-Channel Receive Buffer require a minimum cycle time (t
3. Read access time is measured from the falling edge of CS or the falling edge of RD, whichever occurs last.
4. CS may go Low before either RD or WR goes Low.
5. In minimal systems, CS may be tied Low.
6. Read and write indirect register operations cannot be mixed without at least one write command register operation between
7. CS may go High before either RD or WR goes High.
8. If CS goes High before WR goes High, the minimum Address Hold time becomes 12 ns.
9. RD and WR pulse width, Address setup and hold, and Data setup and hold timing are measured from the points where both
80
Parameter Symbol
t
t
t
t
t
t
t
t
Parameter Symbol
t
t
t
t
t
t
t
t
RLRH
RHRL
AVRL
AHRH
RHCH
RACC
RHDZ
RDCS
WLWH
WHWL
AVWL
AHWH
WHCH
DSWH
DHWH
WRCS
read data register operation when accessing the MAP coefficient RAM. This operation requires a minimum recovery time of
450 ns.
them.
CS and RD or WR are Low simultaneously.
Parameter Description
RD Pulse Width
Read Recovery Time (Notes 1, 2)
Address Valid to RD Low
Address Hold After RD High
RD High to CS High (Note 7)
Read Access Time (Note 3)
RD High to Data Hi-Z
RD Low to CS Low (Note 4)
Parameter Description
WR Pulse Width
Write Recovery Time (Note 1)
Address Valid to WR Low
Address Hold After WR High (Note 8)
WR High to CS High (Note 7)
Data Setup to WR High
Data Hold After WR High
WR Low to CS Low (Note 4)
Am79C30A/32A Data Sheet
RLRH
+ t
RHRL
Min
200
200
Min
200
200
100
) of 480 ns.
20
10
20
10
10
0
0
Max
Max
80
50
30
30
Units
Units
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns