9 interrupt set register (isr) – Texas Instruments TMS320C67X/C67X+ DSP User Manual

Page 46

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Control Register File

CPU Data Paths and Control

2-20

SPRU733

2.7.9 Interrupt Set Register (ISR)

The interrupt set register (ISR) allows you to manually set the maskable inter-
rupts (INT15−INT4) in the interrupt flag register (IFR). Writing a 1 to any of the
bits in ISR causes the corresponding interrupt flag (IFn) to be set in IFR. Writ-
ing a 0 to any bit in ISR has no effect. You cannot set any bit in ISR to affect
NMI or reset. The ISR is shown in Figure 2−10 and described in Table 2−11.

Note:
Any write to ISR (by the MVC instruction) effectively has one delay slot

because the results cannot be read (by the MVC instruction) in IFR until two

cycles after the write to ISR.
Any write to the interrupt clear register (ICR) is ignored by a simultaneous

write to the same bit in ISR.

Figure 2−10. Interrupt Set Register (ISR)

31

16

Reserved

R-0

15

14

13

12

11

10

9

8

7

6

5

4

3

0

IS15 IS14 IS13 IS12 IS11 IS10

IS9

IS8

IS7

IS6

IS5

IS4

Reserved

W-0

R-0

Legend: R = Read only; W = Writeable by the MVC instruction; -n = value after reset

Table 2−11. Interrupt Set Register (ISR) Field Descriptions

Bit

Field

Value Description

31−16 Reserved

0

Reserved. The reserved bit location is always read as 0. A value written to this
field has no effect.

15−4

ISn

Interrupt set.

0

Corresponding interrupt flag (IFn) in IFR is not set.

1

Corresponding interrupt flag (IFn) in IFR is set.

3−0

Reserved

0

Reserved. The reserved bit location is always read as 0. A value written to this
field has no effect.

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