SLDS145B Datasheet, PDF (14/29 Pages) Texas Instruments – TFP410 TI PanelBus DIGITAL TRANSMITTER

TFP410
TI PanelBus™ DIGITAL TRANSMITTER
SLDS145B − OCTOBER 2001 − REVISED MAY 2011
data de-skew feature
The de-skew feature allows adjustment of the input setup/hold time. Specifically, the input data DATA[23:0] can
be latched slightly before or after the latching edge of the clock IDCK± depending on the amount of de-skew
desired. When de-skew enable (DKEN) is enabled, the amount of de-skew is programmable by setting the three
bits DK[3:1]. When disabled, a default de-skew setting is used. To allow maximum flexibility and ease of use,
DKEN and DK[3:1] are accessed directly through configuration pins when I²C is disabled, or through registers
of the same name when I²C is enabled. When using I²C mode, the DKEN pin should be tied to ground to avoid
a floating input.
The input setup/hold time can be varied with respect to the input clock by an amount t_(CD) given by the formula:
t_(CD) = (DK[3:1] – 4) × t_(STEP)
Where:
t_(STEP) is the adjustment increment amount
DK[3:1] is a number from 0 to 7 represented as a 3-bit binary number
t_(CD) is the cumulative de-skew amount
(DK[3:1]-4) is simply a multiplier in the range {-4,-3,-2,-1, 0, 1, 2, 3} for t_(STEP). Therefore, data can be latched
in increments from 4 times the value of t_(STEP) before the latching edge of the clock to 3 times the value of t_(STEP)
after the latching edge. Note that the input clock is not changed, only the time when data is latched with respect
to the clock.
DATA[23:0]
IDCK±
−t_(CD)
t_(CD)
−t_(CD)
t_(CD)
DK[3:1]
t_(CD)
000
−4 × t_(STEP)
100
0
Default Falling
111
000
3 × t_(STEP) −4 × t_(STEP)
100
0
Default Rising
111
3 × t_(STEP)
Figure 8. A Graphical Representation of the De-Skew Function
hot plug/unplug (auto connect/disconnect detection)
TFP410 supports hot plug/unplug (auto connect/disconnect detection) for the DVI link. The receiver sense input
(RSEN) bit indicates if a DVI receiver is connected to TXC+ and TXC-. The HTPLG bit reflects the current state
of the HTPLG pin connected to the monitor via the DVI connector. When I²C is disabled (ISEL=0), the RSEN
value is available on the MSEN pin. When I²C is enabled, the connection status of the DVI link and HTPLG sense
pins are provided by the CTL_2_MODE register. The MSEL bits of the CTL_2_MODE register can be used to
program the MSEN to output the HTPLG value, the RSEN value, an interrupt, or be disabled.
The source of the interrupt event is selected by TSEL in the CTL_2_MODE register. An interrupt is generated
by a change in status of the selected signal. The interrupt status is indicated in the MDI bit of CTL_2_MODE
and can be output via the MSEN pin. The interrupt continues to be asserted until a 1 is written to the MDI bit,
resetting the bit back to 0. Writing 0 to the MDI bit has no effect.
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