LMH0303 Datasheet, PDF (7/14 Pages) National Semiconductor (TI) – 3 Gbps HD/SD SDI Cable Driver with Cable Detect

7. The Device drives an ACK bit “0”.
8. The Device drives the 8-bit data value (register contents).
9. The Host drives a NACK bit “1”indicating end of the
READ transfer.
10. The Host drives a STOP condition.
Application Information
Figure 1 shows the application circuit for the LMH0303.
FIGURE 1. Application Circuit
30043202
COMMUNICATING WITH MULTIPLE LMH0303 CABLE
DRIVERS VIA THE SMBus
A common application for the LMH0303 will utilize multiple
cable driver devices. Even though the LMH0303 devices all
have the same default SMBus device ID (address), it is still
possible for them share the SMBus signals as shown in
Figure 2. A third signal is required from the host to the first
device. This signal acts as a “Enable / Reset” signal. Addi-
tional LMH0303s are controlled from the upstream device. In
this control scheme, multiple LMH0303s may be controlled
via the two-wire SMBus and the use of one GPO (General
Purpose Output) signal. Other SMBus devices may also be
connected to the two wires, assuming they have their own
unique SMBus addresses.
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