r6781-12 Conexant Systems, Inc., r6781-12 Datasheet - Page 21

• Manufacturer Part Number: r6781-12
• Description: Embedded Modem Family
• Manufacturer: Conexant Systems, Inc.

EmbeddedModem Family
D224ATLVDSC
Register (Addr = 2)
7
0
Interrupt Identifier
6
0
The Interrupt Identifier Register (IIR) identifies the existence and type of
prioritized pending interrupts. Four priority levels are set to assist interrupt
processing in the host.
interrupt pending and acknowledges no other interrupts until the particular
interrupt is serviced by the host.
Bits 3-7:
PL0-1
IP
When addressed during chip-select time, the IIR freezes the highest priority
5
0
4
0
Not used (always 0).
Highest Priority Pending Interrupt. These two bits identify
the highest priority pending interrupt.
2
1
1
0
0
Interrupt Pending. When this bit is a logic 0, an interrupt is
pending. When this bit is a logic 1, no interrupt is pending.
This bit can be used in a hardwired prioritized or polled
environment to indicate whether an interrupt is pending. If an
interrupt is pending, the IIR contents can be used as a pointer
to the appropriate interrupt service routine in the host.
Conexant
1
1
0
1
0
3
0
Priority
(highest)
2
3
4
Level
PL1
2
Pending Interrupt
Receiver Line Status
Receiver Buffer Full
Transmitter Holding Register
Empty
Modem Status
PL0
1
2.1 Hardware Interface
IP
0
2-7