
Data Sheet
June 2001
DSP16410B Digital Signal Processor
Agere Systems Inc.
Agere Systems—Proprietary
Use pursuant to Company instructions
285
11 Timing Characteristics and Requirements
(continued)
11.9 System and External Memory Interface
In the following timing diagrams and associated tables:
I
The designation ENABLErefers to one of the following pins: EROMN, ERAMN, or EION. The designation
ENABLES refers to all of the following pins: EROMN, ERAMN, and EION.
I
The designation ERWNrefers to:
—The ERWN0 pin if the external data bus is configured as 16 bits, i.e., if the ESIZE pin is logic low.
—The ERWN1 and ERWN0 pins if the external data bus is configured as 32 bits, i.e., if the ESIZE pin is logic
high.
—The ERWN1, ERWN0, and EA0 pins if the external data bus is configured as 32 bits, i.e., if the ESIZE pin is
logic high, and if the memory access is synchronous.
I
The designation EArefers to:
—The external address pins EA[18:0] and the external segment address pins ESEG[3:0] if the external data bus
is configured as 16 bits, i.e., if the ESIZE pin is logic low.
—The external address pins EA[18:1] and the external segment address pins ESEG[3:0] if the external data bus
is configured as 32 bits, i.e., if the ESIZE pin is logic high.
I
The designation EDrefers to:
—The external data pins ED[31:16] if the external data bus is configured as 16 bits, i.e., if the ESIZE pin is logic
low.
—The external data pins ED[31:0] if the external data bus is configured as 32 bits, i.e., if the ESIZE pin is logic
high.
I
The designation ATIME refers to IATIME (
ECON0
[11:8]) for accesses to the EIO space, YATIME (
ECON0
[7:4])
for accesses to the ERAM space, or XATIME (
ECON0
[3:0]) for accesses to the EROM space.
ECKO reflects CLK, i.e.,
ECON1
[1:0] = 1.
Figure 75. Enable and Write Strobe Transition Timing
Table 195. Timing Characteristics for ERWN and Memory Enables
Abbreviated Reference
t102
t103
t112
t113
Parameter
Min
0.5
0.5
0.5
0.5
Max
4
4
4
4
Unit
ns
ns
ns
ns
ECKO to ENABLEActive (high to low)
ECKO to ENABLEInactive (high to high)
ECKO to ERWNActive (high to low)
ECKO to ERWNInactive (high to high)
ENABLE
t102
ERWN
t113
t112
t103
ECKO
V
OH
–
V
OL
–