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Texas Instruments MSC1210 User Manual

Page 119

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Types of Interrupts

10-13

Interrupts

The AISTAT (A7

H

) is a read-only SFR that returns the current state of interrupt

conditions that are enabled. Any condition that is configured to provoke an in-
terrupt and is currently true will return a 1. Any condition that is not currently
true or was not configured to provoke an interrupt will return a 0.

Table 10−10. AISTAT (A7

H

) SFR

Bit

Name

Explanation of Function

Clear Interrupt

7

SEC

Detect seconds auxiliary interrupt

Read SECINT

6

SUM

Detect summation auxiliary interrupt

Read SUMR0

5

ADC

Detect ADC conversion auxiliary interrupt

Read ADRESL

4

MSEC

Detect millisecond auxiliary interrupt

Read MSINT

3

SPIT

Detect SPI transmit auxiliary interrupt

Write SPIDATA

2

SPIR

Detect SPI receive auxiliary interrupt

Read SPIDATA

1

ALVD

Detect analog low-voltage auxiliary interrupt

Voltage above
threshold

0

DLVD

Detect digital low-voltage or breakpoint auxil-
iary interrupt

Write BP = 1

Note:

AISTAT is read-only. A value may not be written to this SFR with the expecta-
tion of triggering the specific auxiliary interrupt. An auxiliary interrupt may be
triggered by setting the EICON.4 (AI) flag, but which auxiliary interrupt will
be triggered in software cannot be specified.

When an Auxiliary interrupt occurs, the MSC1210 will vector to the ISR at
0033

H

. The code of the ISR may use the Pending Auxiliary Interrupt (PAI, A5

H

)

SFR to determine which of the auxiliary interrupts provoked the actual inter-
rupt.

Table 10−11. PAI (A5

H

) SFR

Bit

Name

Explanation of Function

7

Undefined

6

Undefined

5

Undefined

4

Undefined

3

PAI3

Bit 3 of Auxiliary Interrupt Index

2

PAI2

Bit 2 of Auxiliary Interrupt Index

1

PAI1

Bit 1 of Auxiliary Interrupt Index

0

PAI0

Bit 0 of Auxiliary Interrupt Index