Confidential Draft
3/7/00
CS4281 Programming Manual
80
DS308PRM1
10.4
Interrupt Reporting Registers
10.4.1
Host Interrupt Status Register (HISR)
Address:
BA0: 000h, Read-Only
Default:
00000000h
Definition: Core powered. The Host Interrupt Status register provides interrupt source information to the host
interrupt service routine. Reading this register does NOT clear any interrupt. Interrupts are
cleared from their respective sources. Each interrupt source has a corresponding mask bit in
HIMR register.
Bit Descriptions:
INTENA
Current state of internal interrupt enable bit. First read after interrupt will show
INTENA
= 1
(not cleared until end of/after read). Subsequent reads of HISR will show
INTENA
= 0 until
EOI issued.
MIDI
MIDI port interrupt. Caused by UART receiving data. Cleared by reading the MIDSR register.
FIFOI
FIFO polled mode interrupt. Cleared by using
FIFO[3:0]
to select FIFO causing the interrupt.
Then reading the respective FCHSn register (reads clear the interrupt condition).
DMAI
DMA interrupt, either end of DMA or half of transfer. Cleared by using
DMA[3:0]
to select
DMA engine causing the interrupt. Then reading the correct HDSRn register.
FIFO[3:0] FIFOn interrupt status. A 1 indicates the FIFOn that’s causing the FIFOI flag. Cleared by
reading the associated FCHSn register for the FIFO(s) that caused the interrupt.
DMA[3:0] DMAn engine interrupt status. A 1 indicates the DMAn that’s causing the
DMAI
flag. Cleared
by reading the associated HDSRn register.
GPPI
General Purpose Input pin from Primary AC ‘97 Link (
ASDIN
) caused an interrupt (Slot 12,
GP_INT
bit). This interrupt is cleared by writing a 0 to the
GPPS
bit in the GPIOR register (see
Figure 52); however, since the interrupt condition occurred in the Primary codec, it must be
removed by writing to the Primary Codec (
ACCTL.TC
= 0) GPIO Pin Sticky register, Index
54h.
GPSI
General Purpose Input pin from Secondary AC ‘97 Link (
ASDIN2
) caused an interrupt
(Slot 12,
GP_INT
bit). This interrupt is cleared by writing a 0 to the
GPSS
bit in the GPIOR
register (see Figure 52); however, since the interrupt condition occurred in the Secondary
codec, it must be removed by writing to the Secondary Codec (
ACCTL.TC
= 1) GPIO Pin
Sticky register, Index 50h.
GP3I
GPIO3 pin caused an interrupt. Cleared by writing a 0 to the
GP3S
bit in the GPIOR register.
GP1I
The
ASDIN2/GPIO1
(configured as a
GPIO1
input) caused an interrupt. Cleared by writing a 0
to the
GP1S
bit in the GPIOR register.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
INTENA
res
MIDI
res
FIFOI
res
DMAI
res
res
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FIFO3
FIFO2
FIFO1
FIFO0
DMA3
DMA2
DMA1
DMA0
GPPI
GPSI
GP3I
GP1I
VUPI
VDNI
D
ra
ft
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