LMH0307 Datasheet, PDF (8/14 Pages) National Semiconductor (TI) – 3 Gbps HD/SD SDI Dual Cable Driver with Cable Detect

FIGURE 2. SMBus Configuration for Multiple LMH0307 Cable Drivers
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The RSTI pin of the first device is controlled by the system
with a GPO pin from the host. The first LMH0307 RSTO pin
is then daisy chained to the next device's RSTI pin. That
device’s RSTO pin is connected to the next device and so on.
The procedure at initialization is to:
1. Hold the host GPO pin Low in RESET, to the first device.
RSTO output default is also Low which holds the next
device in RESET in the chain.
2. Raise the host GPO signal to LMH0307 #1 RSTI input
pin
3. Write to Address 8’h2E (7’h17) Register 0 with the new
address value (e.g. 8’h2C (7’h16)
4. Upon writing Register 0 in LMH0307 #1, its RSTO signal
will switch High. Its new address is 8’h2C (7’h16), and
the next LMH0307 in the chain will now respond to the
default address of 8’h2E (7’h17).
5. The process is repeated until all LMH0307 devices have
a unique address loaded.
6. Direct SMBus writes and reads may now take place
between the host and any addressed device.
The 7-bit address field allows for 128 unique addresses. The
above procedure allows for the reprogramming of the
LMH0307 devices such that multiple devices may share the
two-wire SMBus. Make sure all devices on the bus have
unique device IDs.
If power is toggled to the system, the SMBus address routine
needs to be repeated.
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