ST18-AU1 STMICROELECTRONICS [STMicroelectronics], ST18-AU1 Datasheet - Page 38

• Manufacturer Part Number: ST18-AU1
• Description: SIX-CHANNEL DOLBY AC3/MPEG2 AUDIO DECODER
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST18-AU1
IPR: Interrupt priority register
(Address = 002A, Reset = 0000h, Read/Write)
The IPR register contains the priority level of each ITRQ0-7 interrupt input. IP0-7 priority level
is coded using two bits. The different values of IP are 0, 1, 2, 3 (0 lowest priority, 3 highest
priority).
When two ITRQ with the same priority level are requesting during the same cycle, the first
acknowledged interrupt is the one corresponding to the lowest number (for example, ITRQ0
acknowledged prior to ITRQ3).
ISPR: Interrupt stack pointer register
(Address = 002B, Reset = 0000h, Read/Write)
Note:
ISPR contains the number of stacked priority levels. If the ISPR value is directly written, the
SPLi/CPL values are modified. So the ICR register content is no longer significant but the
interrupt routine procedure is not affected. After reset, ISPR default value is 0
ISR: Interrupt status register
(Address = 002C, Reset = 0000h, Read/Write)
Note:
38/87
Bit
IP
Bit
ISPR
Bit
IPE
15
15
15
IP7(1:0)
-
-
14
14
14
-
-
’-’ is RESERVED (read: 0, write: don’t care)
‘-’ is RESERVED (read: 0, write: don’t care)
13
13
13
IP6(1:0)
Function
Interrupt priority level (0, 1, 2 or 3) (default is 0)
Function
Number of stacked priority levels (0, 1, 2 or 3)
Function
Interrupt pending bit
-
-
0: Reset when interrupt request is acknowledged (default)
1: Set when interrupt request is recorded
12
12
12
-
11
11
11
IP5(1:0)
-
-
10
10
10
-
-
IP4(1:0)
9
9
9
-
-
8
8
8
-
-
IPE7 IPE6 IPE5 IPE4 IPE3 IPE2 IPE1 IPE0
IP3(1:0)
7
7
7
-
6
6
6
-
IP2(1:0)
5
5
5
-
4
4
4
-
3
IP1(1:0)
3
3
-
2
2
2
ISP(2:0)
1
1
IP0(1:0)
1
0
0
0