Interrupts

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Interrupts
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Two levels of interrupt management

• Level 0
• Level 1

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Level 0 Interrupt Management

• Static creation of interrupt vector table for the
  interrupt controller mechanism with interrupt
  handlers of all other peripheral interrupts
• Libgen statically creates the interrupt vector
  table based on all interrupt handlers declared

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Level 1 interrupt management

• Libgen does nothing
• User must dynamically register interrupts
  handlers and enable/disable interrupts
• You probably dont want to do this

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Interrupt Handlers

• You have to write your own interrupt handlers (or
  interrupt service routines)
• The main interrupt handler needs to be tagged
  with interrupt_handler attributes so the
  microblaze knows where to go in case of an
  interrupt being raised
• If you use an interrupt controller, Libgen will
  do the tagging for you

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Interrupt Controller

• A peripheral you can add to your system
• If you specify any interrupts on uarts or timers
  during system generation, the base system builder
  will automatically throw in an interrupt
  controller, free of charge
• On any interrupt, the controller interrupt
  handler will call the ISRs you have specified for
  that particular inerrupt
• If more than one device interrupts, highest
  priority device will be handled first

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Interrupt Controller
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Enabling interrupts

• Whenever you need to enable interrupts, call
  microblaze_enable_interrupts()
• Strangely enough, microblaze_disable_interrupts()
  will disable interrupts.

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Single Interrupt System

• If you only have one interrupt, an interrupt
  controller is not needed
• You can still use one if you feel like it
• Need to hook up the interrupt port on your device
  with the interrupt port on the microblaze
• You also must specify the interrupt handler in
  the MSS file

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MSS File
BEGIN DRIVER PARAMETER DRIVER_NAME tmrctr
PARAMETER DRIVER_VER 1.00.b PARAMETER
HW_INSTANCE opb_timer_1 PARAMETER int_handler
timer_int_handler, int_port Interrupt END
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MHS File
BEGIN microblaze PARAMETER INSTANCE
microblaze_0 PARAMETER HW_VER 2.00.a
PARAMETER C_DEBUG_ENABLED 0 PARAMETER
C_NUMBER_OF_PC_BRK 1 PARAMETER
C_NUMBER_OF_RD_ADDR_BRK 0 PARAMETER
C_NUMBER_OF_WR_ADDR_BRK 0 BUS_INTERFACE DOPB
mb_opb BUS_INTERFACE IOPB mb_opb
BUS_INTERFACE DLMB dlmb BUS_INTERFACE ILMB
ilmb PORT CLK sys_clk_s PORT Interrupt
interrupt END
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MHS File cont
BEGIN opb_timer PARAMETER INSTANCE
opb_timer_1 PARAMETER HW_VER 1.00.b PARAMETER
C_COUNT_WIDTH 32 PARAMETER C_ONE_TIMER_ONLY
0 PARAMETER C_BASEADDR 0x00006300 PARAMETER
C_HIGHADDR 0x000063ff BUS_INTERFACE SOPB
mb_opb PORT OPB_Clk sys_clk_s PORT Interrupt
interrupt END
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code
void timer_int_handler(void baseaddr_p)
int baseaddr (int )baseaddr_p Blah blah
blah junk blah blah