3
Program Control
3 – 17
ICNTL Interrupt Nesting Enable bit = 0 (nesting disabled)
Interrupt
IMASK contents before
IMASK contents entering
level serviced
(pushed on stack)
interrupt service routine
0 (low)
ijklmn
000000
1
ijklmn
000000
2
ijklmn
000000
3
ijklmn
000000
4
ijklmn
000000
5 (high)
ijklmn
000000
ICNTL Interrupt Nesting Enable bit = 1 (nesting enabled)
Interrupt
IMASK contents before
IMASK contents entering
level serviced
(pushed on stack)
interrupt service routine
0 (low)
ijklmn
ijklm0
1
ijklmn
ijkl00
2
ijklmn
ijk000
3
ijklmn
ij0000
4
ijklmn
i00000
5 (high)
ijklmn
000000
(“ijklmn” represents any pattern of ones and zeroes)
Table 3.8 IMASK Entering Interrupt Service Routines (ADSP-2101 example)
3.4.2.3 Global Enable/Disable for Interrupts
Global interrupt enable and disable instructions are available on the
ADSP-2171, ADSP-2181, and ADSP-21msp58/59 processors:
ENA INTS;
DIS INTS;
Interrupts are enabled by default after reset. The
DIS INTS
instruction
causes all interrupts (including powerdown) to be masked out regardless
of the contents of IMASK. The
ENA INTS
instruction allows all
unmasked interrupts to be serviced again.
Disabling interrupts does not affect serial port autobuffering.