MAX7358 Maxim, MAX7358 Datasheet - Page 16

• Manufacturer Part Number: MAX7358
• Description: The MAX7356/MAX7357/MAX7358 8-channel I²C switches/multiplexers expand the main I²C bus to any combination of 8 extended I²C buses
• Manufacturer: Maxim

1-to-8 I
Lock-Up Detection, Isolation, and Notification
Following an interrupt when bit B0 and B7 are enabled,
the bus master can read the stuck high fault byte to
identify stuck channels. A bit set to ”1” indicates that
the associated channel is stuck, and will not be allowed
to be connected to the host bus. The stuck high fault
register is cleared, and, if the interrupt feature is
enabled, RST/INT deasserts (goes to high) once this
register is read. However, while B7 is set to one, any
time a disconnected bus is selected for connection, the
preconnect test runs. If the fault still exists, the fault
handling sequence repeats and the faulty bus will not
be allowed to connect to the host bus.
The RST on the MAX7356 can be used to reset the
MAX7356 by a host. The RST input is an active-low sig-
nal. By asserting this signal low for a minimum of t
externally, the MAX7356 resets its I
and deselects all channels. RST is overvoltage-tolerant
to +6V. The RST input must be connected to V
through a pullup resistor.
Table 7. A Traffic Prior to Lock-Up Register Contents Example
Table 8. Stuck HIGH Fault Register Channel Indication
X = Don’t care.
16
ADDRESS
B7
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
1
0x04
0x05
______________________________________________________________________________________
B6
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
1
B7
0
0
2
C Bus Switches/Multiplexers with Bus
Stuck HIGH Fault Register
B6
B5
1
1
X
X
X
X
X
X
X
X
X
X
0
1
X
X
X
X
(MAX7357/MAX7358)
B5
1
1
B4
X
X
X
X
X
X
X
X
0
1
X
X
X
X
X
X
RST (MAX7356)
B4
2
0
0
C state machine
B3
X
X
X
X
X
X
0
1
X
X
X
X
X
X
X
X
B3
1
0
WL(rst)
B2
B2
0
0
X
X
X
X
0
1
X
X
X
X
X
X
X
X
X
X
DD
B1
0
0
The RST/INT on the MAX7357 or MAX7358 is bidirec-
tional. It can be used to reset the device by a host or by
the device to send an interrupt signal to the host. The
RST/INT input is an active-low signal. By asserting
RST/INT low for a minimum of t
device resets its registers and I
deselects all channels. When RST/INT is configured to
notify the host of fault conditions, and while RST/INT
is being used as an output by the MAX7357 or
MAX7358 (sending an interrupt to the host), it does not
function as a reset input. RST/INT is overvoltage-tolerant
to +6V. RST/INT must be connected to V
pullup resistor.
A bus lock-up-caused interrupt signal can be sent to a
host through the bidirectional RST/INT pin depending
on whether or not bit B0 of the configuration register is
set. Configuration register bit B2 controls how the inter-
rupt signal is reset. When B2 = 0, the interrupt signal
asserts (stays low) until the lock-up indication register is
read. When B2 = 1, the interrupt signal deasserts after
B1
X
X
0
1
X
X
X
X
X
X
X
X
X
X
X
X
B0
0
0
Interrupt Signal (MAX7357/MAX7358)
B0
X
X
X
X
X
X
X
X
X
X
X
X
X
X
0
1
Write to the troubled device address
The first data byte with trailing 0’s due to lock-up
Channel 0 not stuck high
Channel 0 stuck high
Channel 1 not stuck high
Channel 1 stuck high
Channel 2 not stuck high
Channel 2 stuck high
Channel 3 not stuck high
Channel 3 stuck high
Channel 4 not stuck high
Channel 4 stuck high
Channel 5 not stuck high
Channel 5 stuck high
Channel 6 not stuck high
Channel 6 stuck high
Channel 7 not stuck high
Channel 7 stuck high
RST / INT (MAX7357/MAX7358)
NOTE
COMMAND
2
WL(rst)
C state machine and
externally, the
DD
through a