adv7189b Analog Devices, Inc., adv7189b Datasheet - Page 17

• Manufacturer Part Number: adv7189b
• Description: Multiformat Sdtv Video Decoder
• Manufacturer: Analog Devices, Inc.

GLOBAL PIN CONTROL
Three-State Output Drivers
TOD, Address 0x03[6]
This bit allows the user to three-state the output drivers of the
ADV7189B.
Upon setting the TOD bit, the P[19:0], HS, VS, FIELD, and SFL
pins are three-stated.
The timing pins (HS/VS/FIELD) can be forced active via the
TIM_OE bit. For more information on three-state control, refer
to the
Enable sections.
Individual drive strength controls are provided via the
DR_STR_XX bits.
The ADV7189B supports three-stating via a dedicated pin.
When set high, the OE pin three-states the output drivers for
P[19:0], HS, VS, FIELD, and SFL. The output drivers are three-
stated if the TOD bit or the OE pin is set high.
When TOD is 0 (default), the output drivers are enabled.
When TOD is 1, the output drivers are three-stated.
Three-State LLC Drivers
TRI_LLC, Address 0x1D[7]
This bit allows the output drivers for the LLC1 pin and LLC2
pin of the ADV7189B to be three-stated. For more information
on three-state control, refer to the
and the
Individual drive strength controls are provided via the
DR_STR_XX bits.
When TRI_LLC is 0 (default), the LLC pin drivers work
according to the DR_STR_C[1:0] setting (pin enabled).
When TRI_LLC is 1, the LLC pin drivers are three-stated.
Timing Signals Output Enable
TIM_OE, Address 0x04[3]
The TIM_OE bit should be regarded as an addition to the
TOD bit. Setting it high forces the output drivers for HS, VS,
and FIELD into the active (that is, driving) state even if the
TOD bit is set. If set to low, the HS, VS, and FIELD pins are
three-stated dependent on the TOD bit. This functionality is
useful if the decoder is to be used as a timing generator only.
This may be the case if only the timing signals are to be
extracted from an incoming signal, or if the part is in free-
run mode where a separate chip can output, for instance, a
company logo.
For more information on three-state control, refer to the
State Output Drivers and the
T hree-State LLC Drivers and the
1 4 8 H
T iming Signals Output Enable sections.
1 5 1 H
T hree-State LLC Drivers sections.
1 5 3 H
T hree-State Output Drivers
1 5 0 H
1 4 9 H
T iming Signals Output
T hree-
1 5 2 H
Rev. B | Page 17 of 104
Individual drive strength controls are provided via the
DR_STR_XX bits.
When TIM_OE is 0 (default), HS, VS, and FIELD are three-
stated according to the TOD bit.
When TIM_OE is 1, HS, VS, and FIELD are forced active all
the time.
Drive Strength Selection (Data)
DR_STR[1:0] Address 0xF4[5:4]
For EMC and crosstalk reasons, it can be desirable to strengthen
or weaken the drive strength of the output drivers. The
DR_STR[1:0] bits affect the P[19:0] output drivers.
For more information on three-state control, refer to the
Strength Selection (Clock) and the
(Sync) sections.
Table 11. DR_STR_C Function
DR_STR_C[1:0]
00
01 (default)
10
11
Drive Strength Selection (Clock)
DR_STR_C[1:0] Address 0xF4[3:2]
The DR_STR_C[1:0] bits can be used to select the strength of
the clock signal output driver (LLC pin). For more information,
refer to the
Strength Selection (Data) sections.
Table 12. DR_STR_C Function
DR_STR_C[1:0]
00
01 (default)
10
11
Drive Strength Selection (Sync)
DR_STR_S[1:0] Address 0xF4[1:0]
The DR_STR_S[1:0] bits allow the user to select the strength of
the synchronization signals with which HS, VS, and F are driven.
For more information, refer to the
(Clock) and the
Table 13. DR_STR_S Function
DR_STR_S[1:0]
00
01 (default)
10
11
D rive Strength Selection (Sync) and the
1 5 6 H
D rive Strength Selection (Data) sections.
1 5 9 H
Description
Low drive strength (1×).
Medium low drive strength (2×).
Medium high drive strength (3×).
High drive strength (4×).
Description
Low drive strength (1×).
Medium low drive strength (2×).
Medium high drive strength (3×).
High drive strength (4×).
Description
Low drive strength (1×).
Medium low drive strength (2×).
Medium high drive strength (3×).
High drive strength (4×).
D rive Strength Selection
1 5 8 H
1 5 5 H
D rive Strength Selection
ADV7189B
D rive
1 5 7 H
D rive
1 5 4 H