Intel
®
81341 and 81342—I
2
C Bus Interface Units
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
940
Order Number: 315037-002US
16.8.6
I
2
C Manual Bus Control Register x — IMBCRx
The I
2
C Manual Bus Control Register (IMBCRx) can be used to manually release or pull
down the
SCL
and
SDA
pins. The values of these pins are controlled by the IMBCRx
bits 2:1 when bit 0 of the IMBCRx is set. When software determines that the I
2
C bus is
hung using the
“I2C Bus Monitor Register x — IBMRx” on page 939
, this register may
be used to force the I
2
C bus out of the hung state.
Note:
When the I
2
C bus is hung, the I
2
C unit should also be reset using bit 14 of the
Control Register x — ICRx” on page 933
Table 593. I
2
C Manual Bus Control Register x — IMBCRx
Bit
Default
Description
31:03
0
Reserved
02
0
SDA
Control: When bit 0 of the IMBCRx is set, this bit controls the
SDA
pin.
0 = Pull Down the
SDA
pin
1 = Do Not Pull Down the
SDA
pin
01
0
SCL
Control: When bit 0 of the IMBCRx is set, this bit controls the
SCL
pin.
0 = Pull Down the
SCL
pin
1 = Do Not Pull Down the
SCL
pin
00
0
Manual I
2
C
Pin Control Enable: When set, the
SCL
and
SDA
pins are controlled by bits 1 and 2 of the
IMBCRx register. Otherwise, these pins are controlled by the I
2
C
unit’s internal state machine.
PCI
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rw
na
rw
na
rw
na
Unit #
0
1
2
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
Intel XScale
®
processor internal bus address
offset
+2518H
+2538H
+2558H