BCM1250/BCM1125/BCM1125H
User Manual
10/21/02
B r o a d c o m C o r p o r a t i o n
Page
374
Section 11: Generic/Boot Bus
Document
1250_1125-UM100CB-R
G
ENERIC
B
US
R
EGISTERS
Table 251: Generic Bus Region Configuration Registers
io_ext_cfg_0 -
00_1006_1000
io_ext_cfg_1 -
00_1006_1008
io_ext_cfg_2 -
00_1006_1010
io_ext_cfg_3 -
00_1006_1018
io_ext_cfg_4 -
00_1006_1020
io_ext_cfg_5 -
00_1006_1028
io_ext_cfg_6 -
00_1006_1030
io_ext_cfg_7 -
00_1006_1038
A write to any bit causes all bits to be written.
Bits
Name
Default
Description
0
rdy_active
1'b0
When low the IO_RDY is active low (i.e. the device lets the line go low when it is
ready), when high IO_RDY is active high.
1
io_ena_rdy
1'b0
When high, the interface uses acknowledgement based access. (See also bit 0)
3:2
io_width_sel
2'h0
Select the data width size.
2'b00: 1 byte width (default for
_0
bootmode 01)
2'b01: 2 byte width
2'b10: Alternate 8 bit width (mux on D[7:0])
2'b11: 4 byte width (default for cs0 bootmode 00, 10, 11)
4
io_parity_ena
1'b0
When high, enable parity check.
5
io_burst_en
1'b0
When high the interface will use the burst mode to run each transaction.
6
io_parity_type
1'b0
When low even parity is used, when high odd parity is used.
7
io_nonmux
1'b0
When high the bus is used in non-multiplexed mode with AD[31:24] being 8 bits of
data and AD[23:0] being 24 bits of address. If the io_width_sel is not set to 2'b00 (for
8 bits) then bus operation is UNPREDICTABLE. For
_0
, the default is 1 in bootmode
01 and 0 in other bootmodes.
15:8
io_timeout
8'h8
Time out value. Unit is 1 us. If this field is zero the access will never timeout.
63:16
notimp
48’bx
Not Implemented.
Table 252: Generic Bus Region Size Registers
io_ext_mult_size_0 -
00_1006_1100
io_ext_mult_size_1 -
00_1006_1108
io_ext_mult_size_2 -
00_1006_1110
io_ext_mult_size_3 -
00_1006_1118
io_ext_mult_size_4 -
00_1006_1120
io_ext_mult_size_5 -
00_1006_1128
io_ext_mult_size_6 -
00_1006_1130
io_ext_mult_size_7 -
00_1006_1138
A write to any bit causes all bits to be written.
Bits
Name
Default
Description
11:0
io_mult_size
12'h0
Size of the memory region in the multiple of 64KB.
The region size is (io_mul 1)*64KB
15:12
reserved
4'h0
Reserved
63:16
notimp
48’bx
Not implemented.