
Data Sheet
June 2001
DSP16410B Digital Signal Processor
100
Agere Systems—Proprietary
Use pursuant to Company instructions
Agere Systems Inc.
4 Hardware Architecture
(continued)
4.14 System and External Memory Interface (SEMI)
(continued)
4.14.1 External Interface
Table 51
provides an overview of the SEMI pins. These pins are described in detail in the remainder of this section.
Table 51. Overview of SEMI Pins
Function
Clock
Configuration
Pin
ECKO
ESIZE
Type
O
I
Description
External clock.
Size of external SEMI data bus:
ESIZE = 0 selects 16-bit data bus.
ESIZE = 1 selects 32-bit data bus.
EROM type:
ERTYPE
I
ERTYPE = 0 selects asynchronous memory for the EROM component.
ERTYPE = 1 selects synchronous pipelined ZBTSRAM for the EROM component.
Boot source:
EXM
I
EXM = 0 selects IROM.
EXM = 1 selects EROM.
External request for SEMI bus (negative assertion).
SEMI acknowledge for external request (negative assertion).
External device ready for asynchronous access.
ERAM component enable (negative assertion).
EROM component enable (negative assertion).
EIO component enable (negative assertion).
External read/write not:
Bus Arbitration
for Asynchronous
Memory
EREQN
EACKN
ERDY
ERAMN
EROMN
EION
ERWN[1:0]
I
O
I
Enables
and Strobes
O/Z
O/Z
O/Z
O/Z
If ESIZE = 0 (16-bit external bus):
ERWN1: Inactive (logic high).
ERWN0: Write enable (negative assertion).
If ESIZE = 1 (32-bit external bus):
ERWN1: Odd word (least significant 16 bits) write enable (negative assertion).
ERWN0: Even word (most significant 16 bits) write enable (negative assertion).
I/O/Z Bidirectional 32-bit external data bus.
O/Z
External address bus bits 18—1.
O/Z
If ESIZE = 0:
Address
and Data
ED[31:0]
EA[18:1]
EA0
External address bus bit 0.
If ESIZE = 1 and the external component is synchronous
:
Write strobe (negative assertion).
External segment address.
This pin determines the mode of the external data bus. It must be static and tied to
V
SS
(if the SEMI is used) or V
DD
2 (if the SEMI is not used). If EYMODE = 0, the exter-
nal data bus ED[31:0] operates normally as described above. If EYMODE = 1,
ED[31:0] are statically configured as outputs (regardless of the state of RSTN) and
must not be connected externally. If EYMODE = 1, external pull-up resistors are not
needed on ED[31:0]. See
Section 10.1 on page 269
for details.
The EROM component is synchronous if the ERTYPE pin is logic 1. The ERAM component is synchronous if YTYPE field (
ECON1
[9]) is set and the
EIO component is synchronous if the ITYPE field (
ECON1
[10]) is set.
ECON1
is described in
Table 60 on page 110
.
ESEG[3:0]
EYMODE
O/Z
I