TLC34075A Datasheet, PDF (30/53 Pages) Texas Instruments – Video Interface Palette Data Manual

Table 2– 8. General Control Register Bit Functions
GENERAL CONTROL REGISTER BIT
76543210
FUNCTION
X X X X X X X 0 HSYNCOUT is active-low
X X X X X X X 1 HSYNCOUT is active-high (default)
X X X X X X 0 X VSYNCOUT is active-low
X X X X X X 1 X VSYNCOUT is active-high (default)
X X X X X 0 X X Disable split shift register transfer (default)
X X X X 0 1 X X Enable split shift register transfer
X X X X 0 X X X Disable special nibble mode (default)
X X X X 1 0 X X Enable special nibble mode
X X X 0 X X X X 0-IRE pedestal (default)
X X X 1 X X X X 7.5-IRE pedestal
X X 0 X X X X X Disable sync (default)
X X 1 X X X X X Enable sync
X 0 X X X X X X Reserved (default)
X 1 X X X X X X Reserved
0 X X X X X X X MUXOUT is low (default)
1 X X X X X X X MUXOUT is high
2.11.1 HSYNCOUT and VSYNCOUT (Bits 0 and 1)
HSYNCOUT and VSYNCOUT polarity inversion is provided to allow indication to monitors of the current
screen resolution. Since the polarities for VGA pass-through mode are provided at the feature connector,
the inputs to the TLC34075A will have the right polarities for monitors already, so the TLC34075A just
passes them through with pipeline delay (see Section 2.8). These two bits only work in the normal modes,
and the input horizontal and vertical syncs are assumed to be active-low incoming pulses. These two bits
default to the value 1 but can be changed by software.
2.11.2 Split Shift Register Transfer Enable (SSRT) and Special Nibble Mode Enable
(SNM) (Bits 2 and 3)
See Section 2.9.
2.11.3 Pedestal Enable Control (Bit 4)
This bit specifies whether a 0- or 7.5-IRE blanking pedestal is to be generated on the video outputs. Having
a 0-IRE blanking pedestal means that the black and blank levels are the same.
0: 0-IRE pedestal (default)
1: 7.5-IRE pedestal
2.11.4 Sync Enable Control (Bit 5)
This bit specifies whether or not SYNC information is to be output onto IOG.
0: Disable sync (default)
1: Enable sync
2.11.5 MUXOUT (Bit 7)
The MUXOUT bit indicates to external circuitry that the device is running in VGA pass-through mode. This
bit does not affect the operation of the device (see Section 2.10).
0: MUXOUT is low (default in VGA pass-through mode)
1: MUXOUT is high
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