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
416
Section 14: Serial Configuration Interface
Document
1250_1125-UM100CB-R
Table 292: SMBus Status Registers
smb_status_0 -
00_1006_0020
smb_status_1 -
00_1006_0028
Read clears finish interrupt
Bits
Name
Default
Description
0
smb_busy
1'b0
When high, indicates the serial interface is busy; when low, it is not busy.
1
smb_error
1'b0
When high, indicates an error has occurred. If the smb_mk bit in the
smb_control
register has a value of 1'b1, an interrupt will be generated. The interrupt and this
status bit are cleared by writing this bit with a 1.
2
error_type
1'h0
When bit 1 is high this bit indicates the error that occurred. This bit is cleared if an
expected acknowledgement is not seen and set if the transfer has failed after 15
retries.
5
smb_scl_in
1’bx
Reserved. Will be used to provide value on SCL pin in later revisions of the part.
4:3
reserved
2'b0
Reserved
6
smb_ref
1'b0
In direct mode (smb_direct set in the control register) this bit shows the output of
the serial clock generator (that would be driven to the clock pin in normal mode).
Software may use this as a reference clock. If direct mode is not enabled this bit is
zero.
7
smb_data_in
1'b0
In direct mode (smb_direct set in the control register) this bit shows the value on
the data pin, otherwise it is zero.
63:8
notimp
56’bx
Not implemented.
Table 293: SMBus Data Registers
smb_data_0 -
00_1006_0050
smb_data_1 -
00_1006_0058
Read returns value from previous smbus read command. Write sets value for next smbus write command.
Bits
Name
Default
Description
7:0
smb_lb
8'h0
Least significant data byte that was read ( or will be written) across the serial bus.
15:8
smb_mb
8'h0
Most significant data byte that was read (or will be written) across the serial bus.
63:16
notimp
48’bx
Not implemented.
Table 294: SMBus Extra Data Registers
smb_xtra_0 -
00_1006_0000
smb_xtra_1 -
00_1006_0008
Read returns value from previous smbus read command. Write sets value for next smbus write command.
Bits
Name
Default
Description
7:0
smb_lb
8'h0
Third data byte that was read in an EEPROM read transfer.
15:8
smb_mb
8'h0
Fourth data byte that was read in an EEPROM read transfer.
63:16
notimp
48’bx
Not implemented.