User Manual
BCM1250/BCM1125/BCM1125H
10/21/02
B r o a d c o m C o r p o r a t i o n
Document
1250_1125-UM100CB-R
Section 11: Generic/Boot Bus Page
375
Table 253: Generic Bus Region Base Address Registers
io_ext_start_addr_0 -
00_1006_1200
io_ext_start_addr_1 -
00_1006_1208
io_ext_start_addr_2 -
00_1006_1210
io_ext_start_addr_3 -
00_1006_1218
io_ext_start_addr_4 -
00_1006_1220
io_ext_start_addr_5 -
00_1006_1228
io_ext_start_addr_6 -
00_1006_1230
io_ext_start_addr_7 -
00_1006_1238
A write to any bit causes all bits to be written.
Bits
Name
Default
Description
13:0
io_start_addr
14'h0
Bits [29:16] of start address of segment. If this address is outside the generic bus
range then the region is disabled.
14
reserved
1’b0
Reserved
15
io_blk_cache
1’b0
If this bit is set then cacheable accesses to this region will be blocked.
63:16
notimp
48’bx
Not implemented.
Table 254: Generic Bus Region Timing 0 Registers
io_ext_time_cfg0_0 -
00_1006_1600 (defaults for boot ROM)
io_ext_time_cfg0_1 -
00_1006_1608
io_ext_time_cfg0_2 -
00_1006_1610
io_ext_time_cfg0_3 -
00_1006_1618
io_ext_time_cfg0_4 -
00_1006_1620
io_ext_time_cfg0_5 -
00_1006_1628
io_ext_time_cfg0_6 -
00_1006_1630
io_ext_time_cfg0_7 -
00_1006_1638
A write to any bit causes all bits to be written.
Bits
Name
Default
Description
2:0
io_ale_width
_0
3’h4
3'h1
Width of IO_ALE.
3
early_cs
1'b0
If this bit is set the external chip select is asserted during the ale_width and ale_to_cs
gap as well as at the normal time. Note that this bit only affects the external signal, the
timing follows the internal chip select asserting in the normal cycle.
5:4
io_ale_to_cs
_0
2’h2
2'h1
Chip select assertion after deassertion of IO_ALE.
7:6
burst_width
2'b0
Sets the gap between data transfers during a burst. The actual gap is burst 2.
12:8
io_cs_width
_0
5’h18
5'h1
Width of the chip select asserted. If the interface is in acknowledgement mode this is the
number of cycles from IO_CS_L being asserted before IO_RDY will start to be checked.
15:13
io_rdy_smple
3'h1
Number of clock cycles after the assertion of the acknowledgement is returned that the
data is sampled into the interface. This is ignored if the interface is in fixed cycle mode.
63:16
notimp
48‘bx
Not implemented
Содержание BCM1125
Страница 18: ...BCM1250 BCM1125 BCM1125H User Manual 10 21 02 Broadcom Corporation Page xviii Document 1250_1125 UM100CB R ...
Страница 28: ...BCM1250 BCM1125 BCM1125H User Manual 10 21 02 Broadcom Corporation Page xxviii Document 1250_1125 UM100CB R ...
Страница 515: ...BCM1250 BCM1125 BCM1125H User Manual 10 21 02 Broadcom Corporation Page vii Index Document 1250_1125 UM100CB R ...