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Interrupts and Interrupt Controller (INTC)
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor
10-39
10.5.2.1
Software Vector Mode
interrupt_exception_handler:
code to create stack frame, save working register, and save SRR0 and SRR1
lis
r3,INTC_IACKR_PRCn@ha
# form adjusted upper half of INTC_IACKR_PRCn address
lwz
r3,INTC_IACKR_PRCn@l(r3)
# load INTC_IACKR_PRCn, which clears request to processor
lwz
r3,0x0(r3)
# load address of ISR from vector table
wrteei
1
# enable processor recognition of interrupts
code to save rest of context required by e500 EABI
mtlr
r3
# move address of ISR into link register
blrl
# branch to ISR; link register updated with epilog
# address
epilog:
code to restore most of context required by e500 EABI
# Popping the LIFO after the restoration of most of the context and the disabling of processor
# recognition of interrupts eases the calculation of the maximum stack depth at the cost of
# postponing the servicing of the next interrupt request.
mbar
# ensure store to clear flag bit has completed
lis
r3,INTC_EOIR_PRCn@ha
# form adjusted upper half of INTC_EOIR address
li
r4,0x0
# form 0 to write to INTC_EOIR_PRCn
wrteei
0
# disable processor recognition of interrupts
stw
r4,INTC_EOIR_PRCn@l(r3)
# store to INTC_EOIR_PRCn, informing INTC to lower priority
code to restore SRR0 and SRR1, restore working registers, and delete stack frame
rfi
vector_table_base_address:
address of ISR for interrupt with vector 0
address of ISR for interrupt with vector 1
.
.
.
address of ISR for interrupt with vector 510
address of ISR for interrupt with vector 511
ISR
x
:
code to service the interrupt event
code to clear flag bit which drives interrupt request to INTC
blr
# return to epilog
10.5.2.2
Hardware Vector Mode
This interrupt exception handler is useful with processor and system bus implementations which support
a hardware vector. This example assumes that each
interrupt_exception_handlerx
only has space for four
instructions, and therefore a branch to
interrupt_exception_handler_continuedx
is needed.
interrupt_exception_handler
x
:
b
interrupt_exception_handler_continued
x
# 4 instructions available, branch to continue
interrupt_exception_handler_continuedx:
Summary of Contents for PXN2020
Page 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Page 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Page 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Page 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Page 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
Page 372: ...e200z6 Core Z6 PXN20 Microcontroller Reference Manual Rev 1 13 8 Freescale Semiconductor...
Page 412: ...e200z0 Core Z0 PXN20 Microcontroller Reference Manual Rev 1 14 14 Freescale Semiconductor...
Page 821: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 27 49...
Page 822: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 27 50 Freescale Semiconductor...
Page 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...