
Data Sheet
June 2001
DSP16410B Digital Signal Processor
110
Agere Systems—Proprietary
Use pursuant to Company instructions
Agere Systems Inc.
4 Hardware Architecture
(continued)
4.14 System and External Memory Interface (SEMI)
(continued)
4.14.4 Registers
(continued)
4.14.4.2 ECON1 Register
The
ECON1
register (
Table 60
) reports status information and controls additional features of the SEMI. If any of
the external memory components (ERAM, EROM, or EIO) are configured as synchronous
1
, the ECKO[1:0] field of
this register must be set to zero to select f
CLK
/2 for the ECKO pin.
Table 60. ECON1 (External Control 1) Register
The memory address for this register is 0x40002.
15—12
11
10
Reserved
WEROM
ITYPE
1. The EROM component is synchronous if the ERTYPE pin is logic 1. The ERAM component is synchronous if the YTYPE field (
ECON1
[9]) is
set. The EIO component is synchronous if the ITYPE field (
ECON1
[10]) is set.
ECON1
is described in
Table 60
.
9
8
7
6
5
4
3—2
1—0
YTYPE
NOSHARE
Reserved
EREADY
EACKN
EREQN
Reserved
ECKO[1:0]
Bit
Field
Value
Description
R/W Reset
Value
0
0
15—12
11
Reserved
WEROM
0
0
Reserved—write with zero.
The external portion of Y-memory and Z-memory space is ERAM (see
Section 4.5.3 on page 38
).
The external portion of Y-memory and Z-memory space is EROM (see
Section 4.5.3 on page 38
).
EION is asynchronous SRAM.
EION is pipelined, synchronous SRAM.
ERAMN is asynchronous SRAM.
ERAMN is pipelined, synchronous SRAM.
SEMI works as a bus-shared interface and asserts EACKN in response to
EREQN.
SEMI ignores requests for the external bus and does not assert EACKN.
Reserved—write with zero.
The ERDY pin indicates an external device is requesting the SEMI to extend the
current asynchronous external memory access (see
Table 53 on page 102
).
The ERDY pin indicates an external device is not requesting the SEMI to extend
the current asynchronous external memory access (see
Table 53 on page 102
).
The EACKN pin indicates the SEMI acknowledges a request by an external
device for access to external memory (see
Table 53 on page 102
).
The EACKN pin indicates the SEMI does not acknowledge a request by an exter-
nal device for access to external memory (see
Table 53 on page 102
).
The EREQN pin indicates an external device is requesting access to external
memory (see
Table 53 on page 102
).
The EREQN pin indicates an external device is not requesting access to external
memory (see
Table 53 on page 102
).
Reserved—write with zero.
The SEMI external clock (ECKO pin) is CLK/2 for synchronous operation of the
SEMI.
The SEMI external clock (ECKO pin) is the internal clock CLK.
The SEMI external clock (ECKO pin) is the buffered input clock pin CKI.
The SEMI external clock (ECKO pin) is held low.
R/W
R/W
1
10
ITYPE
0
1
0
1
0
R/W
0
9
YTYPE
R/W
0
8
NOSHARE
R/W
0
1
0
0
7
6
Reserved
EREADY
R/W
R
0
P
1
5
EACKN
0
R
1
1
4
EREQN
0
R
P
1
3—2
1—0
Reserved
ECKO[1:0]
0
R/W
R/W
0
00
00
01
10
11
The state is a reflection of the state of the external pins and is unaffected by reset.