Start
Stage A
PIEIFRx.y=1
?
Wait for any
PIEIFRx.y=1
No
Wait for
PIEIERx.y=1
Stage B
PIEIERx.y=1
?
No
PIEACKx=0
Stage C
?
No
Wait for
S/W to clear
PIEACKx bit=0
Yes
Yes
Yes
Hardware sets
PIEACKx=1
Stage D
Interrupt request
sent to 28x CPU
on INTx
Interrupts
to CPU
Stage E
IFRx bit set 1
Yes
Stage G
INTM bit=0
?
No
Yes
IERx bit=1
Stage F
?
No
Stage H
CPU responds
IFRx=0, IERx=0
INTM=1, EALLOW=0
Context Save performed
Stage I
Vector fetched from the PIE
PIEIFRx.y is cleared
CPU branches to ISR
Stage J
Interrupt service routine responds
Write 1 to PIEACKx bit to clear
to enable other interrupts in
PIEIFRx group
Re-enable interrupts, INTM=0
Return
End
CPU interrupt control
PIE interrupt control
A.
For multiplexed interrupts, the PIE responds with the highest priority interrupt that is both flagged and enabled. If there is no interrupt
both flagged and enabled, then the highest priority interrupt within the group (INTx.1 where x is the PIE group) is used. See
for details.
Figure 1-94. Typical PIE/CPU Interrupt Response - INTx.y
, the requirements for enabling the maskable interrupt at the CPU level depends on the
interrupt handling process being used. In the standard process, which happens most of the time, the DBGIER
register is not used. When the 28x is in real-time emulation mode and the CPU is halted, a different process is
used. In this special case, the DBGIER is used and the INTM bit is ignored. If the DSP is in real-time mode and
the CPU is running, the standard interrupt-handling process applies.
Table 1-116. Enabling Interrupt
Interrupt Handling Process
Interrupt Enabled If…
Standard
INTM = 0 and bit in IER is 1
DSP in real-time mode and halted
Bit in IER is 1 and DBGIER is 1
System Control and Interrupts
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
169
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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