AZ Displays Dev Board AZD-A7N-1GB
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Control the GPIO in Linux system
Using sunxi-gpio kernel module
1. Make sure that the newest firmware has loaded the module gpio-sunxi.ko by default
and it has added the command include fex2bin bin2fex. (Use the command 'lsmod' to
see the module in the list.)
2. Modify script.bin that configuration file of AZD-A7N-1GB.
modify script.bin
$ mount /dev/nanda /mnt
$ cd
/mnt
$ bin2fex script.bin script.fex
$ vi script.fex
Default GPIO paragraph setup:
[gpio_para]
gpio_used =1
gpio_num = 2
gpio_pin_1 = port: PH20<1><default><default><1>
green LED
//PH20 is connecting
the
gpio_pin_2 = port: PH21<1><default><default><1>
blue LED
//PH21 is connecting
the
Modify GPIO port want to use e.g.:
[gpio_para]
gpio_used =1
gpio_num = 3
gpio_pin_1 = port: PD01<1><default><default><1>
gpio_pin_2 = port: PD02<1><default><default><1>
gpio_pin_3 = port: PD03<1><default><default><1>
Save the file, then
AZ Displays Dev Board AZD-A7N-1GB
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$ fex2bin script.fex script.bin
$ reboot
After rebooted the AZD-A7N-1GB, the new setup will be effective.
3. Operate GPIO port e.g.:
open the GPIO PD01~03
$ echo 1 > /sys/class/gpio/export
$ echo 2 > /sys/class/gpio/export
$ echo 3 > /sys/class/gpio/export
Below the /sys/class/gpio has appeared directories named gpio1_pd01, gpio2_pd02,
gpio3_pd03.
set the PD01 por as output
$ cd /sys/class/gpio/gpio1_pd01
$ echo out > direction
set the PD01 port as high
$ echo 1 > value
set the PD01 port as low
$ echo 0 > value
Using C program without driver
The demo control the PD01 port blink led :
#include <stdlib.h>
#include <stdio.h>
#include "gpio_lib.h"
#define PD0
SUNXI_GPD(0)
#define PD1
SUNXI_GPD(1)
#define PD2
SUNXI_GPD(2)
#define PD3
SUNXI_GPD(3)
#define PD4
SUNXI_GPD(4)
#define MISO
SUNXI_GPE(3)
#define MOSI
SUNXI_GPE(2)
AZ Displays Dev Board AZD-A7N-1GB
#define SCK
SUNXI_GPE(1)
#define CS
SUNXI_GPE(0)
int main()
{
if(SETUP_OK!=sunxi_gpio_init()){
printf("Failed to initialize GPIO\n");
return -1;
}
if(SETUP_OK!=sunxi_gpio_set_cfgpin(PD01,OUTPUT)){
printf("Failed to config GPIO pin\n");
return -1;
}
int i;
for(i=0;i<5;i++){
if(sunxi_gpio_output(PD01,HIGH)){
printf("Failed to set GPIO pin value\n");
return -1;
}
usleep(500000);
if(sunxi_gpio_output(PD01,LOW)){
printf("Failed to set GPIO pin value\n");
return -1;
}
usleep(500000);
}
sunxi_gpio_cleanup();
return 0;
}
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AZ Displays Dev Board AZD-A7N-1GB
www.azdisplays.com
Save as gpio.c,download gpio_lib,then
$sudo apt-get install gcc build-essential
$tar -xf gpio.tar
$cd gpio/
$gcc gpio_lib.c -c
$gcc gpio.c -c
$gcc gpio.o gpio_lib.o -o gpio
$./gpio
If you have used a led connect GND and PD01 port,the led is going to blink in cycle time.
Of course you can define and use other port .
Use above the method like high-delay-low-delay to simulate PWM output .
Using mmap mapping IO address
///////////////////////////////////////////////////////////////////////////////
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <time.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/select.h>
#include <pthread.h>
#include <unistd.h>
#include <sched.h>
#include <errno.h>
#define SW_PORTC_IO_BASE
0x01c20800
AZ Displays Dev Board AZD-A7N-1GB
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int main() {
unsigned int * pc;
int fd, i;
char * ptr;
unsigned int addr_start, addr_offset, PageSize, PageMask, data;
PageSize = sysconf(_SC_PAGESIZE);
PageMask = (~(PageSize-1));
addr_start = SW_PORTC_IO_BASE & PageMask;
addr_offset = SW_PORTC_IO_BASE & ~PageMask;
fd = open("/dev/mem", O_RDWR);
if(fd < 0) {
perror("Unable to open /dev/mem");
return(-1);
}
pc = mmap(0, PageSize*2, PROT_READ|PROT_WRITE, MAP_SHARED, fd,
addr_start);
if(pc == MAP_FAILED) {
perror("Unable to mmap file");
printf("pc:%lx\n", (unsigned long)pc);
return(-1);
}
printf("PageSize:%8.8x\tPageMask:%8.8x\naddr_start:%8.8x\taddr_offset:%8.8x\n",Pa
geSize,PageMask,addr_start,addr_offset);
printf("pc:%8.8x\n", *(unsigned int *)pc);
ptr = (char *)pc + addr_offset;
data = *(unsigned int *)(ptr+0x10c);
for(i=0;i<1000;i++){
data |= 1<<20;
*(unsigned int *)(ptr+0x10c) = data;
usleep(100000);
//green led connect PH20
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data &= ~(1<<20);
*(unsigned int *)(ptr+0x10c) = data;
usleep(500000);
}
return 0;
}
save as test.c,then
$sudo apt-get install gcc build-essential
$gcc test.c -o test
$./test &
The green LED is blinking in cycle time. You can modify the data |= 1«20; and data &=
~(1«20); to use PH15 like data |= 1«15; and data &= ~(1«15);.If you have used a led connect
VCC and PH15 port, the led is going to blink in cycle time.
Using Python program
Install python and lib
$sudo apt-get update
$sudo apt-get install python-dev
$wget http://www.azdisplays.com/download/devboard/tools/pySUNXI-0.1.12.tar.gz
$tar zxf pySUNXI-0.1.12.tar.gz
$sudo python setup.py install
Connect the GPIO
Using the PD0 and VCC-5V for test.
AZ Displays Dev Board AZD-A7N-1GB
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AZ Displays Dev Board AZD-A7N-1GB
Write a sample program
#!/usr/bin/env python
import SUNXI_GPIO as GPIO
import time
RED_LED = GPIO.PD0
GPIO.init()
GPIO.setcfg(RED_LED, GPIO.OUT)
while True:
GPIO.output(RED_LED, GPIO.HIGH)
time.sleep(1)
GPIO.output(RED_LED, GPIO.LOW)
time.sleep(1)
Run program
$chmod +x blink.py
$sudo ./blink.py
The red LED will blink in cycle time.
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