Table 5. configuration register definition – Rainbow Electronics MAX7358 User Manual
Page 14
MAX7356/MAX7357/MAX7358
1-to-8 I
2
C Bus Switches/Multiplexers with Bus
Lock-Up Detection, Isolation, and Notification
14
______________________________________________________________________________________
B7
B6
B5
B4
B3
B2
B1
B0
COMMAND
X
X
X
X
X
X
X
0
Interrupt with
RST/INT disabled
X
X
X
X
X
X
X
1
Interrupt with
RST/INT enabled
X
X
X
X
X
X
0
X
Flush-out disabled
X
X
X
X
X
X
1
X
Flush-out enabled
X
X
X
X
X
0
X
X
RST/INT released after a register read
X
X
X
X
X
1
X
X
RST/INT released after 1.6 seconds
X
X
X
X
0
X
X
X
The lock-up register shows the current
condition
X
X
X
X
1
X
X
X
The lock-up register data is not cleared
until a read
X
X
X
0
X
X
X
X
Disconnect all channels on bus lock-up
X
X
X
1
X
X
X
X
Disconnect only the locked up bus
X
X
0
X
X
X
X
X
Bus lock-up detection enabled
X
X
1
X
X
X
X
X
Bus lock-up detection disabled
X
0
X
X
X
X
X
X
Enhanced mode
X
1
X
X
X
X
X
X
Basic mode enabled
0
X
X
X
X
X
X
X
Preconnect test is disabled
1
X
X
X
X
X
X
X
Preconnect test is enabled
Table 5. Configuration Register Definition
X = Don’t care.
be selected. More than one channel can be selected
simultaneously. When a channel is selected, the channel
becomes active immediately after a stop condition has
been placed on the I
2
C bus. This ensures that all
SC_/SD_ lines are in a HIGH state when the channel is
made active, so that no false conditions are generated at
the time of connection.
Configuration Register
(MAX7357/MAX7358)
B0 = RST/INT serves as an interrupt when a bus lock-
up condition is detected.
B1 = Flush-out sequence is sent automatically on locked-
up channels when a lock-up condition is detected.
B2 = When B0 = 1, release the RST/INT output after
asserting for 1.6 seconds.
B3 = Data in the lock-up indication register cleared only
after reading the register.
B4 = Connected channels remain connected on detec-
tion of lock-up if the lock-up condition is present only on
a channel that is not connected.
B5 = Disable bus lock-up detection.
B6 = Basic mode.
B7 = Enables the preconnection wiggle test for SC_
and SD_.
Flush-Out Sequence Register
(MAX7357/MAX7358)
A flush-out sequence can be sent to a particular auxil-
iary bus automatically after the identification of the lock-
up condition. The flush-out sequence consists of 18
SC_ clock cycles. An 8-bit sequence for the SD_ to fol-
low during the flush-out cycle can also be defined by
writing to the flush-out sequence register. By default,
the flush-out sequence register is all ones. The
MAX7357 or MAX7358 attempt to send the one-byte
sequence followed by an additional clock cycle (NACK)
two times sequentially, followed by a stop condition.
The effectiveness of sending the flush-out sequence
depends on the behavior of the locked-up device. For
an auxiliary bus with only slave devices, it is more likely
that the SCL line can still be driven by the MAX7357 or
MAX7358. In this case, a slave device may respond to
a particular flush-out sequence. After the release of the
SD_ line by a “stuck” device, the remaining sequence
on the SD_ line can be used to reset itself.
Bus Lock-Up Indication Register
(MAX7357/MAX7358)
The bus master can read the lock-up indication byte to
identify the stuck channels. A bit set to ”1” indicates
that the associated channel is stuck. The indication for
a given channel remains as long as the lock-up condi-