T8207-BAL-DT Agere Systems, Inc., T8207-BAL-DT Datasheet - Page 24

• Manufacturer Part Number: T8207-BAL-DT
• Description: CelXpres ATM interconnect. Dry-bagget, tape & reel .
• Manufacturer: Agere Systems, Inc.

CelXpres T8207
ATM Interconnect
6
6.3.1
Before accessing the extended memory registers, the powerup sequence, as described in Section 3, Powerup/
Reset Sequence, must be completed. Accesses to extended memory are word accesses internally; therefore, the
least significant bit of the address is always ‘0.’ Only the most significant 25 bits are supplied to the extended mem-
ory address registers (addresses 30h—34h). The following procedure outlines the steps needed for extended
memory accesses in the T8207 device.
6.3.1.1
1.
2.
3.
4.
5.
6.
7.
8.
6.3.1.2
1.
2.
3.
4.
5.
6.
7.
8.
Note:
24
Write ext_a [25] bit to the extended memory address 4 register (little endian or big endian) (optional).
Write ext_a [24:17] byte to the extended memory address register 3 (little endian or big endian) (optional).
Write ext_a [16:9] byte to the extended memory address register 2 (little endian or big endian) (optional).
Write ext_a [8:6] bits to the extended memory address register 1 (little endian or big endian) (optional).
Write ext_d [15:8] byte to the extended memory data high register (little endian or big endian) (optional).
Write ext_d [7:0] byte to the extended memory data low register (little endian or big endian) (optional).
Write ext_a [5:1] bits; write “01,” “10,” or “11” to ext_we[1:0]; and write ‘1’ to ext_strt_acc in the extended mem-
ory access register (little endian or big endian) (mandatory).
Read the extended memory access register (little endian or big endian) to determine that the ext_strt_acc bit
has been cleared by hardware (mandatory).
Write ext_a [25] bit to the extended memory address 4 register (little endian or big endian) (optional).
Write ext_a [24:17] byte to the extended memory address register 3 (little endian or big endian) (optional).
Write ext_a [16:9] byte to the extended memory address register 2 (little endian or big endian) (optional).
Write ext_a [8:6] bits to the extended memory address register 1 (little endian or big endian) (optional).
Write ext_a [5:1] bits; write “00” to ext_we[1:0]; and write ‘1’ to ext_strt_acc in the extended memory access
register (little endian or big endian) (mandatory).
Read the extended memory access register (little endian or big endian) to determine that the ext_strt_acc bit
has been cleared by hardware (mandatory).
Read ext_d [15:8] byte from the extended memory data high register (little endian or big endian) (optional).
Read ext_d [7:0] byte from the extended memory data low register (little endian or big endian) (optional).
Microprocessor Interface
Accessing the Extended Memory Registers
Once the ext_strt_acc bit is set by software, only the extended memory access register should be
accessed until the ext_strt_acc bit is cleared by hardware.
Extended Memory Writes
Extended Memory Reads
(continued)
Advance Data Sheet
September 2001
Agere Systems Inc.