2nd program: Use C language to illuminate an LED

2. A total of three files: head. S LED_ON_C.C Makefile

4. Head. The contents of s are as follows:

5. 1 /*2* * Time: 2016year April 8: About: *3 * * location: Dormitory. 4 * * Function: Initialize some hardware related things, call C function. 5 **  6 * * Additional information:7**1, operating Environment: JZ2440V2 Development Board. 8**2, program compilation Environment: UBUNTU9.Ten+ cross-compilation tool ARM-LINUX-GCC. 9**3, the registers used are: Gpfcon, Gpfdat, Wtcon. Ten**4, the pin that the led1 receives is the GPF4 pin.  One */ A  - . equ Wtcon, 0X53000000 @ macro definition Wtcon to 0x53000000 -  the . Text -  - . Global _start -  + _start: - / * Close the watchdog to prevent the CPU from constantly starting. */ + Ldr R0, = Wtcon A     movR1, #0 at     StrR1, [R0] -  - / * Set the stack first before calling the C function. */ -Ldr sp, =4096 -  - / * Call the C function. */ in BL main -  to Halt_loop: +b halt_loop

7. LED_ON_C.C content is as follows:

8. 1 /* 2* * Time: 2016year April 8: to: at3 * * location: Dormitory. 4 * * Function: Light the first led:led1. 5 */6 7 #define GPFCON * (volatile unsigned long *) 0x56000050)8 #define GPFDAT * (volatile unsigned long *) 0x56000054)9 Ten intmain (void) One { A / * Configure the GPF4 pin as the output pin. */ -Gpfcon = 0x00000100; -  the / * Let the GPF4 pin output low, light led1. */ -Gpfdat = 0x00000000; -  -while (1); +  -Return0; +}

10. The contents of the makefile file are as follows:

12. #
    #时间: April 8, 2016 17:11:09
    #

    Led_on_c.bin:head. S LED_ON_C.C
    Arm-linux-gcc-wall-g-C head. S-o HEAD.O
    Arm-linux-gcc-wall-g-C Led_on_c.c-o LED_ON_C.O
    Arm-linux-ld-ttext 0x00000000-g HEAD.O Led_on_c.o-o led_on_c_elf
    Arm-linux-objcopy-o binary-s led_on_c_elf Led_on_c.bin
    arm-linux-objdump-d-M arm led_on_c_elf > Led_on_c_elf.dis
    arm-linux-objdump-d-B binary-m arm led_on_c.bin > Led_on_c_bin.dis

    Clean:
    Rm-f *.o *.dis *.bin *elf

2nd program: Use C language to illuminate an LED