S3C2440——Keyboard interrupt service routine

S3C2440 keyboard module circuit

There are a total of S1, S2, S3, and S4 buttons, which correspond to the four interrupt sources EINT19, EINT2, EINT0, and EINT11 respectively. The interrupt framework and service routine are as follows:

Interrupt response, take out the keyboard number (1-4) that triggered the interrupt and put it in R5

;FileASM_Interrupt.s

;(1)Set the interrupt vector table

Mode_USR EQU 0x50 ; IRQ interrupt is open, FIQ interrupt is closed

Mode_FIQ EQU 0xD1 ; turn off IRQ and FIQ interrupts

Mode_IRQ EQU 0xD2 ; turn off IRQ and FIQ interrupts

Mode_SVC EQU 0xD3 ; turn off IRQ and FIQ interrupts

GET 2440Reg_addr.inc

    AREA MyCode, CODE,READONLY

IMPORT initial_keyboard_INT

    ENTRY ;Set interrupt vector table

B ResetHandler ;Reset interrupt service routine

B. ; handlerUndef

B. ; SWI interrupt handler

B. ; handlerPAbort

B. ; handlerDAbort

B. ; handlerReserved

B HandlerIRQ ;HandlerIRQ

B. ; HandlerFIQ

;(2)Reset interrupt handler

ResetHandler

BL Clock_Init ; initialize watchdog, clock

;BL MemSetup ;Initialize SDRAM

  LDR      SP, =SvcStackSpace ;Set management mode stack

        MSR CPSR_c, #Mode_IRQ

        LDR SP, =IrqStackSpace ; Set IRQ interrupt mode stack

        MSR CPSR_c, #Mode_FIQ

        LDR SP, =FiqStackSpace ; Set FIQ interrupt mode stack

        MSR CPSR_c, #Mode_USR ;Enter user mode

LDR SP, =UsrStackSpace ; Set user and system mode stack

  ;BL Init_DATA ;Initialize readable and writable data

BL initial_keyboard_INT

LDR R0,=pEINT0;EINT0 address in the interrupt entry transfer table

LDR R1,=EINT0 ;R1 interrupt service routine entry address

STR R1,[R0] ;EINT0 interrupt program entry address is written into the interrupt transfer table

LDR R0,=pEINT2;EINT2 address in the interrupt entry transfer table

LDR R1,=EINT2 ;R1 interrupt service routine entry address

STR R1,[R0] ;EINT2 interrupt program entry address is written into the interrupt transfer table

LDR R0,=pEINT8_23;EINT8_23 address in the interrupt entry transfer table

LDR R1,=EINT8_23 ;R1 interrupt service routine entry address

STR R1,[R0] ;EINT8_23 interrupt program entry address is written into the interrupt transfer table

MAIN_LOOP

  NOP

B      MAIN_LOOP ; infinite loop, interrupted by IRQ; initialize readable and writable data area

Clock_Init

GET Clock_Init.s ;Initialize watchdog and clock

MemSetup

GET MemSetup.s ;Initialize SDRAM

Init_DATA

GET Init_DATA.s ; Initialize the readable and writable data area

;(3)IRQ interrupt handler

HandlerIRQ

SUB LR,LR, #4 ; Calculate return address

    STMFD SP!, {LR} ;Save breakpoint to stack in IRQ mode

LDR LR,= Int_Return ; modify LR and return to Int_Return after executing the EINT8_23 handler.

LDR R0,=INTOFFSET ; Get the number of the interrupt source

LDR R1,[R0]

LDR R2,=Int_EntryTable ;Start address of interrupt transfer table

LDR PC,[R2,R1,LSL#2] ; Check the interrupt transfer table and obtain the handler entry address of EINT8_23, which is equivalent to a subroutine call without parameters, but no breakpoints are saved.

Int_Return ; You must return here after executing the EINT8_23 handler.

LDMFD  SP!, {PC }^ ;IRQ interrupt service routine returns, ^ means copying the value of SPSR to CPSR

;EINT0 handler

EINT0

MOV R5,#3

LDR R0,=SRCPND ;Clear several pending registers

    LDR R1,[R0]

    STR R1,[R0]

LDR R0,=INTPND

    LDR R1,[R0]

    STR R1,[R0]

    MOV PC,LR ; Return to IRQ interrupt service routine from EINT0 handler

;EINT2 handler

EINT2

MOV R5,#2

LDR R0,=SRCPND ;Clear several pending registers

    LDR R1,[R0]

    STR R1,[R0]

LDR R0,=INTPND

    LDR R1,[R0]

    STR R1,[R0]

    MOV PC,LR ; Return to IRQ interrupt service routine from EINT2 handler

; (4) EINT8_23 handler

EINT8_23

LDR R0,=EINTPEND ;R0 is set to the EINTPEND register address

LDR R1,[R0] ; Read EINTPEND, 24 bits in total, the lowest 4 bits are reserved

CMP      R1,#0x080000 ; Determine whether EINT19 interrupt

LDREQ  R5,=0x1 ;R5 is the key number

CMP      R1,#0x000800 ; Determine whether EINT11 interrupt

LDREQ  R5,=0x4

LDR R0,=SRCPND ;Clear several pending registers

    LDR R1,[R0]

    STR R1,[R0]

LDR R0,=INTPND

    LDR R1,[R0]

    STR R1,[R0]

LDR R0,=EINTPEND

    LDR R1,[R0]

    STR R1,[R0]

    MOV PC,LR ; Return to IRQ interrupt service routine by EINT8_23 handler

AREA MyRWData, DATA, READWRITE ;Set RW Base=0x33ffe700

Int_EntryTable

GET Int_EntryTable.s ; Interrupt transfer table, 32 entries in total

        AREA MyZIData, DATA, READWRITE, NOINIT,ALIGN=8

;Pushdown stack, according to the alignment, the starting address of the segment is 0x33ffe800, and the space of each stack area is 1k

SPACE 0x100 * 4 ; Management mode stack is empty

SvcStackSpace SPACE 0x100 * 4 ;Interrupt mode stack space

IrqStackSpace SPACE 0x100 * 4 ; fast interrupt mode stack space

FiqStackSpace SPACE 0x100 *

UsrStackSpace

END

;File Int_EntryTable.s, defines the interrupt transfer table

;32 channels in total, corresponding to 32 inputs of the arbiter

pEINT0 DCD 0 ; stores the entry address of the EINT0-3 interrupt service routine

pEINT1 DCD 0

pEINT2 DCD 0

pEINT3 DCD 0

pEINT4_7 DCD 0 ; stores the entry address of the EINT4_7 interrupt service routine

pEINT8_23 DCD 0 ; stores the EINT8_23 interrupt service routine entry address——EINT8_23

pINT_CAM DCD 0 ; stores 26 internal interrupt service routine entry addresses

pnBATT_FLT DCD 0

pINT_TICK DCD 0

pINT_WDT_AC97 DCD 0

…

pINT_UART0 DCD 0

pINT_SPI1 DCD 0

pINT_RTC DCD 0

pINT_ADC DCD 0

END

#include "2440Reg_addr.h" //Special register address definition

void initial_keyboard_INT(void){

    rGPGCON=((0x10<<22)|(0x10<<6)); //Set GPIO as external interrupt pin

    rGPFCON=((0x10|(0x10<<4));//Set GPF as interrupt pin

    rGPGUP=0xffff; // No pull-up

    rGPFUP = 0xff; // No pull-up

    rEINTMASK&=((0x1<<11)|(0x1<<19));//Open EINT11, 19 interrupt

    rEXTINT0=0x0; //All are low level interrupts, no filtering is used

    rEXTINT1=0x0;

    rEXTINT2=0x0;

    rINTMSK=0xFFFFFFD5; //Open interrupt

}