ADV7181 AD [Analog Devices], ADV7181 Datasheet - Page 57

• Manufacturer Part Number: ADV7181
• Description: Multiformat SDTV Video Decoder
• Manufacturer: AD [Analog Devices]

Interrupt Request Output Operation
When an interrupt event occurs, the interrupt pin INTRQ
goes low with a programmable duration given by
INTRQ_DUR_SEL[1:0]
INTRQ_DURSEL[1:0], Interrupt Duration Select
Address 0x40 (Interrupt Space) [7:6]
Table 74. INTRQ_DUR_SEL
INTRQ_DURSEL[1:0]
00
01
10
11
When the “Active until Cleared” interrupt duration is selected
and the event that caused the interrupt is no longer in force, the
interrupt persists until it is masked or cleared.
For example, if the ADV7181B loses lock, an interrupt is
generated and the INTRQ pin goes low. If the ADV7181B
returns to the locked state, INTRQ continues to drive low
until the SD_LOCK bit is either masked or cleared.
Interrupt Drive Level
The ADV7181B resets with open drain enabled and all interrupts
masked off. Therefore, INTRQ is in a high impedance state after
reset. 01 or 10 must to be written to INTRQ_OP_SEL[1:0] for a
logic level to be driven out from the INTRQ pin.
It is also possible to write to a register in the ADV7181B that
manually asserts the INTRQ pin. This bit is MPU_STIM_INTRQ.
Description
3 Xtal Periods (default)
15 Xtal Periods
63 Xtal Periods
Active until Cleared
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INTRQ_OP_SEL[1:0], Interrupt Duration Select
Address 0x40 (Interrupt Space) [1:0]
Table 75. INTRQ_OP_SEL
INTRQ_OP_SEL[1:0]
00
01
10
11
Multiple Interrupt Events
If Interrupt Event 1 occurs and then Interrupt Event 2 occurs
before the system controller has cleared or masked Interrupt
Event 1, the ADV7181B does not generate a second interrupt
signal. The system controller should check all unmasked
interrupt status bits since more than one may be active.
Macrovision Interrupt Selection Bits
The user can select between pseudo sync pulse and color stripe
detection as follows:
MV_INTRQ_SEL[1:0], Macrovision Interrupt Selection Bits
Address 0x40 (Interrupt Space) [5:4]
Table 76. MV_INTRQ_SEL
MV_INTRQ_SEL
[1:0]
00
01
10
11
Additional information relating to the interrupt system is
detailed in Table 82.
Description
Reserved
Pseudo Sync Only (default)
Color Stripe Only
Either Pseudo Sync or Color Stripe
Description
Open Drain (default)
Drive Low when Active
Drive High when active
Reserved
ADV7181B