Firmware Version – FW Ver
FW Ver shows the version of the firmware installed on the evaluation board.
Termination Fault
These controls show the default configuration of the HD and SD Termination Fault Threshold registers and also
provide the ability to change the thresholds. The LMH0307 has two pairs of Termination Fault Threshold registers
– one HD/SD pair for each of its two output channels – as shown in Figure 4. The LMH0303 has only one HD/SD
pair of Termination Fault Threshold registers for its single output channel, as can be seen in Figure 5.
Increasing the Termination Fault Threshold settings decreases the cable driver’s sensitivity to Termination Faults.
This is useful if the cable driver is indicating termination faults when the output appears to be properly terminated.
Decreasing the Termination Fault Threshold settings increases the cable driver’s sensitivity to Termination Faults
which is useful for determining cable detection at the end of long cables.
Compare Command and Termination Fault Counters
Compare Command configures the CMPCMD section of the TEST register (08h) on the LMH0303 or LMH0307.
The Termination Fault Counters reflect the current configuration of the TEST register CMPCMD bits.
The Termination Fault Counters provide an indication of how the cable driver is reading the Termination Faults
based on the current Termination Fault Threshold settings. Perfectly terminated outputs should read back “0”, and
unterminated outputs should read back “31”.
Control
Refresh
The Refresh button provides a manual refresh of the state from the evaluation board to the LMH0303/LMH0307 tab.
Changes to the board will not be reflected in the LED icons and Line Control checkboxes on the
LMH0303/LMH0307 tab until the Refresh button is pressed. This can be done automatically by using the Auto
Refresh checkbox.
Auto Refresh Checkbox
The Auto Refresh checkbox provides an automatic refresh of the state from the evaluation board to the
LMH0303/LMH0307 tab once per second. This provides automatic updating of the LED icons and Line Control
checkboxes on the LMH0303/LMH0307 tab to reflect any board changes.
Line Control
Power Down 0 and 1 (LMH0307 only)
Power Down 0 and 1 checkboxes control the PD0 and PD1 power down bits (bits 5 and 6 in register 02h - MASK)
and will selectively power down one or both of the output channels on the LMH0307.
Enable
The Enable checkbox controls the associated ENABLE pin on the LMH0303/LMH0307. Disabling or un-checking
the Enable checkbox will force the LMH0303/LMH0307 into a deep power down mode.
RSTI
The RSTI checkbox controls the RSTI
¯¯¯¯ pin. This checkbox is checked for normal operation, and un-checked to put
the cable driver in reset.
SD303/SD307 EVK User Guide
10 of 27
Rev 1.2
© 2010, National Semiconductor Corp.
