Linux Device Drivers

Uma visão superficial de como funciona o acesso a dispositivos na parte interna do núcleo do sistema e um exemplo de device drivers.

Transcript

1. SEL630 - PROJETOS DE SISTEMAS DIGITAIS Linux Device Linux Device Drivers Drivers Tiago A. Martins Prof. Dr. Evandro Luís Linhari Rodrigues 1 . 1
2. COMUNICAÇÃO COM O HARDWARE 1 . 2
3. OBJETIVO import RPi.GPIO as gpio led_pin = 23 # Broadcom pin 23 (P1 pin 16) gpio.setmode(gpio.BCM) gpio.setup(led_pin, gpio.OUT) # Let there be light gpio.output(led_pin, gpio.HIGH) 2 . 1
4. OBJETIVO import RPi.GPIO as gpio led_pin = 23 # Broadcom pin 23 (P1 pin 16) gpio.setmode(gpio.BCM) gpio.setup(led_pin, gpio.OUT) # Let there be light gpio.output(led_pin, gpio.HIGH) 2 . 1
5. OBJETIVO import RPi.GPIO as gpio led_pin = 23 # Broadcom pin 23 (P1 pin 16) gpio.setmode(gpio.BCM) gpio.setup(led_pin, gpio.OUT) # Let there be light gpio.output(led_pin, gpio.HIGH) 2 . 1
6. OBJETIVO import RPi.GPIO as gpio led_pin = 23 # Broadcom pin 23 (P1 pin 16) gpio.setmode(gpio.BCM) gpio.setup(led_pin, gpio.OUT) # Let there be light gpio.output(led_pin, gpio.HIGH) 2 . 1
7. OBJETIVO 2 . 2
8. VOLTANDO NO TEMPO 3 . 1
9. MICROCONTROLADORES 3 . 2
10. MICROCONTROLADORES #include <xc.h> int main(void) { TRISB0 = 0; /* RB0 as Output PIN */ while (1) { RB0 = 1; /* LED ON */ __delay_ms(1000); /* 1 Second Delay */ RB0 = 0; /* LED OFF */ __delay_ms(1000); /* 1 Second Delay */ } return 0; } 3 . 2
11. MICROCONTROLADORES #include <xc.h> int main(void) { TRISB0 = 0; /* RB0 as Output PIN */ while (1) { RB0 = 1; /* LED ON */ __delay_ms(1000); /* 1 Second Delay */ RB0 = 0; /* LED OFF */ __delay_ms(1000); /* 1 Second Delay */ } return 0; } 3 . 2
12. MICROCONTROLADORES #include <xc.h> int main(void) { TRISB0 = 0; /* RB0 as Output PIN */ while (1) { RB0 = 1; /* LED ON */ __delay_ms(1000); /* 1 Second Delay */ RB0 = 0; /* LED OFF */ __delay_ms(1000); /* 1 Second Delay */ } return 0; } 3 . 2
13. MICROCONTROLADORES #include <xc.h> int main(void) { TRISB0 = 0; /* RB0 as Output PIN */ while (1) { RB0 = 1; /* LED ON */ __delay_ms(1000); /* 1 Second Delay */ RB0 = 0; /* LED OFF */ __delay_ms(1000); /* 1 Second Delay */ } return 0; } 3 . 2
14. ARM CORTEX-M 3 . 3
15. ARM CORTEX-M void gpio_init_pin(struct gpio_regs *port, unsigned char index, unsigned char pin, struct gpio_pin_config *cfg) { if (cfg->mode & GPIO_MODE_AF) write_reg_pin(&port->alt_func[pin >> GPIO_ALT_FUNC_PIN_SHIFT], pin, GPIO_ALT_FUNC_PIN_W, cfg->alt_func); /* Configure IO Direction mode (Input, Output, Alternate or Analog) */ write_reg_pin(&port->mode, pin, GPIO_MODE_PIN_W, cfg->mode & GPIO_MODE); /* Configure the IO Speed */ write_reg_pin(&port->out_speed, pin, GPIO_OUT_SPEED_PIN_W, cfg->speed); /* Configure the IO Output Type */ write_reg_pin(&port->out_type, pin, GPIO_OUT_TYPE_PIN_W, cfg->mode & GPIO_OUT_TYPE); /* Activate the Pull-up or Pull down resistor for the current IO */ write_reg_pin(&port->pup_pdown, pin, GPIO_PUP_PDOWN_PIN_W, cfg->pull); } 3 . 3
16. ARM CORTEX-M void gpio_init_pin(struct gpio_regs *port, unsigned char index, unsigned char pin, struct gpio_pin_config *cfg) { if (cfg->mode & GPIO_MODE_AF) write_reg_pin(&port->alt_func[pin >> GPIO_ALT_FUNC_PIN_SHIFT], pin, GPIO_ALT_FUNC_PIN_W, cfg->alt_func); /* Configure IO Direction mode (Input, Output, Alternate or Analog) */ write_reg_pin(&port->mode, pin, GPIO_MODE_PIN_W, cfg->mode & GPIO_MODE); /* Configure the IO Speed */ write_reg_pin(&port->out_speed, pin, GPIO_OUT_SPEED_PIN_W, cfg->speed); /* Configure the IO Output Type */ write_reg_pin(&port->out_type, pin, GPIO_OUT_TYPE_PIN_W, cfg->mode & GPIO_OUT_TYPE); /* Activate the Pull-up or Pull down resistor for the current IO */ write_reg_pin(&port->pup_pdown, pin, GPIO_PUP_PDOWN_PIN_W, cfg->pull); } 3 . 3
17. ARM CORTEX-M void gpio_init_pin(struct gpio_regs *port, unsigned char index, unsigned char pin, struct gpio_pin_config *cfg) { if (cfg->mode & GPIO_MODE_AF) write_reg_pin(&port->alt_func[pin >> GPIO_ALT_FUNC_PIN_SHIFT], pin, GPIO_ALT_FUNC_PIN_W, cfg->alt_func); /* Configure IO Direction mode (Input, Output, Alternate or Analog) */ write_reg_pin(&port->mode, pin, GPIO_MODE_PIN_W, cfg->mode & GPIO_MODE); /* Configure the IO Speed */ write_reg_pin(&port->out_speed, pin, GPIO_OUT_SPEED_PIN_W, cfg->speed); /* Configure the IO Output Type */ write_reg_pin(&port->out_type, pin, GPIO_OUT_TYPE_PIN_W, cfg->mode & GPIO_OUT_TYPE); /* Activate the Pull-up or Pull down resistor for the current IO */ write_reg_pin(&port->pup_pdown, pin, GPIO_PUP_PDOWN_PIN_W, cfg->pull); } 3 . 3
18. ARM CORTEX-M void gpio_init_pin(struct gpio_regs *port, unsigned char index, unsigned char pin, struct gpio_pin_config *cfg) { if (cfg->mode & GPIO_MODE_AF) write_reg_pin(&port->alt_func[pin >> GPIO_ALT_FUNC_PIN_SHIFT], pin, GPIO_ALT_FUNC_PIN_W, cfg->alt_func); /* Configure IO Direction mode (Input, Output, Alternate or Analog) */ write_reg_pin(&port->mode, pin, GPIO_MODE_PIN_W, cfg->mode & GPIO_MODE); /* Configure the IO Speed */ write_reg_pin(&port->out_speed, pin, GPIO_OUT_SPEED_PIN_W, cfg->speed); /* Configure the IO Output Type */ write_reg_pin(&port->out_type, pin, GPIO_OUT_TYPE_PIN_W, cfg->mode & GPIO_OUT_TYPE); /* Activate the Pull-up or Pull down resistor for the current IO */ write_reg_pin(&port->pup_pdown, pin, GPIO_PUP_PDOWN_PIN_W, cfg->pull); } 3 . 3
19. ARM CORTEX-M void gpio_init_pin(struct gpio_regs *port, unsigned char index, unsigned char pin, struct gpio_pin_config *cfg) { if (cfg->mode & GPIO_MODE_AF) write_reg_pin(&port->alt_func[pin >> GPIO_ALT_FUNC_PIN_SHIFT], pin, GPIO_ALT_FUNC_PIN_W, cfg->alt_func); /* Configure IO Direction mode (Input, Output, Alternate or Analog) */ write_reg_pin(&port->mode, pin, GPIO_MODE_PIN_W, cfg->mode & GPIO_MODE); /* Configure the IO Speed */ write_reg_pin(&port->out_speed, pin, GPIO_OUT_SPEED_PIN_W, cfg->speed); /* Configure the IO Output Type */ write_reg_pin(&port->out_type, pin, GPIO_OUT_TYPE_PIN_W, cfg->mode & GPIO_OUT_TYPE); /* Activate the Pull-up or Pull down resistor for the current IO */ write_reg_pin(&port->pup_pdown, pin, GPIO_PUP_PDOWN_PIN_W, cfg->pull); } 3 . 3
20. ARM CORTEX-M void gpio_init_pin(struct gpio_regs *port, unsigned char index, unsigned char pin, struct gpio_pin_config *cfg) { if (cfg->mode & GPIO_MODE_AF) write_reg_pin(&port->alt_func[pin >> GPIO_ALT_FUNC_PIN_SHIFT], pin, GPIO_ALT_FUNC_PIN_W, cfg->alt_func); /* Configure IO Direction mode (Input, Output, Alternate or Analog) */ write_reg_pin(&port->mode, pin, GPIO_MODE_PIN_W, cfg->mode & GPIO_MODE); /* Configure the IO Speed */ write_reg_pin(&port->out_speed, pin, GPIO_OUT_SPEED_PIN_W, cfg->speed); /* Configure the IO Output Type */ write_reg_pin(&port->out_type, pin, GPIO_OUT_TYPE_PIN_W, cfg->mode & GPIO_OUT_TYPE); /* Activate the Pull-up or Pull down resistor for the current IO */ write_reg_pin(&port->pup_pdown, pin, GPIO_PUP_PDOWN_PIN_W, cfg->pull); } 3 . 3
21. ARM CORTEX-M void gpio_init_pin(struct gpio_regs *port, unsigned char index, unsigned char pin, struct gpio_pin_config *cfg) { if (cfg->mode & GPIO_MODE_AF) write_reg_pin(&port->alt_func[pin >> GPIO_ALT_FUNC_PIN_SHIFT], pin, GPIO_ALT_FUNC_PIN_W, cfg->alt_func); /* Configure IO Direction mode (Input, Output, Alternate or Analog) */ write_reg_pin(&port->mode, pin, GPIO_MODE_PIN_W, cfg->mode & GPIO_MODE); /* Configure the IO Speed */ write_reg_pin(&port->out_speed, pin, GPIO_OUT_SPEED_PIN_W, cfg->speed); /* Configure the IO Output Type */ write_reg_pin(&port->out_type, pin, GPIO_OUT_TYPE_PIN_W, cfg->mode & GPIO_OUT_TYPE); /* Activate the Pull-up or Pull down resistor for the current IO */ write_reg_pin(&port->pup_pdown, pin, GPIO_PUP_PDOWN_PIN_W, cfg->pull); } void gpio_write_pin(struct gpio_regs *port, unsigned short pin_bit, unsigned char value) { if (value) port->bit_sr = pin_bit; /* set pin */ else port->bit_sr = pin_bit << GPIO_BIT_ST_W; /* reset pin */ } 3 . 3
22. ARM CORTEX-M void gpio_init_pin(struct gpio_regs *port, unsigned char index, unsigned char pin, struct gpio_pin_config *cfg) { if (cfg->mode & GPIO_MODE_AF) write_reg_pin(&port->alt_func[pin >> GPIO_ALT_FUNC_PIN_SHIFT], pin, GPIO_ALT_FUNC_PIN_W, cfg->alt_func); /* Configure IO Direction mode (Input, Output, Alternate or Analog) */ write_reg_pin(&port->mode, pin, GPIO_MODE_PIN_W, cfg->mode & GPIO_MODE); /* Configure the IO Speed */ write_reg_pin(&port->out_speed, pin, GPIO_OUT_SPEED_PIN_W, cfg->speed); /* Configure the IO Output Type */ write_reg_pin(&port->out_type, pin, GPIO_OUT_TYPE_PIN_W, cfg->mode & GPIO_OUT_TYPE); /* Activate the Pull-up or Pull down resistor for the current IO */ write_reg_pin(&port->pup_pdown, pin, GPIO_PUP_PDOWN_PIN_W, cfg->pull); } void gpio_write_pin(struct gpio_regs *port, unsigned short pin_bit, unsigned char value) { if (value) port->bit_sr = pin_bit; /* set pin */ else port->bit_sr = pin_bit << GPIO_BIT_ST_W; /* reset pin */ } 3 . 3
23. ARM CORTEX-M void gpio_init_pin(struct gpio_regs *port, unsigned char index, unsigned char pin, struct gpio_pin_config *cfg) { if (cfg->mode & GPIO_MODE_AF) write_reg_pin(&port->alt_func[pin >> GPIO_ALT_FUNC_PIN_SHIFT], pin, GPIO_ALT_FUNC_PIN_W, cfg->alt_func); /* Configure IO Direction mode (Input, Output, Alternate or Analog) */ write_reg_pin(&port->mode, pin, GPIO_MODE_PIN_W, cfg->mode & GPIO_MODE); /* Configure the IO Speed */ write_reg_pin(&port->out_speed, pin, GPIO_OUT_SPEED_PIN_W, cfg->speed); /* Configure the IO Output Type */ write_reg_pin(&port->out_type, pin, GPIO_OUT_TYPE_PIN_W, cfg->mode & GPIO_OUT_TYPE); /* Activate the Pull-up or Pull down resistor for the current IO */ write_reg_pin(&port->pup_pdown, pin, GPIO_PUP_PDOWN_PIN_W, cfg->pull); } void gpio_write_pin(struct gpio_regs *port, unsigned short pin_bit, unsigned char value) { if (value) port->bit_sr = pin_bit; /* set pin */ else port->bit_sr = pin_bit << GPIO_BIT_ST_W; /* reset pin */ } 3 . 3
24. PROCESSADORES MAIS COMPLEXOS 3 . 4
25. RAZÕES PARA UTILIZAR O SISTEMA OPERACIONAL 3 . 5
26. RAZÕES PARA UTILIZAR O SISTEMA OPERACIONAL Gerenciamento dos recursos 3 . 5
27. RAZÕES PARA UTILIZAR O SISTEMA OPERACIONAL Abstração dos recursos 3 . 5
28. RAZÕES PARA UTILIZAR O SISTEMA OPERACIONAL Segurança 3 . 5
29. ARQUITETURA LINUX 4 . 1
30. LINUX SYSCALLS 4 . 2
31. CHAMADAS GNU LIBC 4 . 3
32. CHAMADAS GNU LIBC int open(const char *filename, int flags[, mode_t mode]) 4 . 3
33. CHAMADAS GNU LIBC ssize_t read(int filedes, void *buffer, size_t size) 4 . 3
34. CHAMADAS GNU LIBC ssize_t write(int filedes, const void *buffer, size_t size) 4 . 3
35. CHAMADAS GNU LIBC off_t lseek(int filedes, off_t offset, int whence) 4 . 3
36. CHAMADAS GNU LIBC size_t fread(void *data, size_t size, size_t count, FILE *stream) 4 . 3
37. CHAMADAS GNU LIBC size_t fwrite(const void *data, size_t size, size_t count, FILE *stream) 4 . 3
38. CHAMADAS GNU LIBC ... 4 . 3
39. CHAMADA EM C 4 . 4
40. SYSCALL 4 . 5
41. FLUXO INTERNO DO KERNEL 4 . 6
42. DEVICE DRIVER 5 . 1
43. ESCREVENDO NO HARDWARE static ssize_t mydev_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) { int i; char *kbuf = kmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; if (copy_from_user(kbuf, buf, count)) return -EFAULT; for (i = 0; i < count; i++) iowrite8((*buf)++, PORT_ADDRESS + (*f_pos)++); } 5 . 2
44. ESCREVENDO NO HARDWARE static ssize_t mydev_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) { int i; char *kbuf = kmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; if (copy_from_user(kbuf, buf, count)) return -EFAULT; for (i = 0; i < count; i++) iowrite8((*buf)++, PORT_ADDRESS + (*f_pos)++); } 5 . 2
45. ESCREVENDO NO HARDWARE static ssize_t mydev_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) { int i; char *kbuf = kmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; if (copy_from_user(kbuf, buf, count)) return -EFAULT; for (i = 0; i < count; i++) iowrite8((*buf)++, PORT_ADDRESS + (*f_pos)++); } 5 . 2
46. ESCREVENDO NO HARDWARE static ssize_t mydev_write(struct file *filp, const char __user *buf, size_t count, loff_t *f_pos) { int i; char *kbuf = kmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; if (copy_from_user(kbuf, buf, count)) return -EFAULT; for (i = 0; i < count; i++) iowrite8((*buf)++, PORT_ADDRESS + (*f_pos)++); } 5 . 2
47. REGISTRANDO AS OPERAÇÕES DE ARQUIVOS #include <linux/fs.h> static struct file_operations mydev_fops = { .owner = THIS_MODULE, .open = mydev_open, .release = mydev_release, .write = mydev_write, .read = mydev_read }; 5 . 3
48. REGISTRANDO AS OPERAÇÕES DE ARQUIVOS #include <linux/fs.h> static struct file_operations mydev_fops = { .owner = THIS_MODULE, .open = mydev_open, .release = mydev_release, .write = mydev_write, .read = mydev_read }; 5 . 3
49. REGISTRANDO AS OPERAÇÕES DE ARQUIVOS #include <linux/fs.h> static struct file_operations mydev_fops = { .owner = THIS_MODULE, .open = mydev_open, .release = mydev_release, .write = mydev_write, .read = mydev_read }; 5 . 3
50. ADICIONANDO O DISPOSITIVO #include <linux/init.h> #include <linux/module.h> static struct class *mydev_class; static int my_init(void) { ... mydev_class = class_create(THIS_MODULE, DRV_NAME); device = device_create(mydev_class, NULL, mydev->id, NULL, "mydev0"); ... } 5 . 4
51. ADICIONANDO O DISPOSITIVO #include <linux/init.h> #include <linux/module.h> static struct class *mydev_class; static int my_init(void) { ... mydev_class = class_create(THIS_MODULE, DRV_NAME); device = device_create(mydev_class, NULL, mydev->id, NULL, "mydev0"); ... } 5 . 4
52. ADICIONANDO O DISPOSITIVO #include <linux/init.h> #include <linux/module.h> static struct class *mydev_class; static int my_init(void) { ... mydev_class = class_create(THIS_MODULE, DRV_NAME); device = device_create(mydev_class, NULL, mydev->id, NULL, "mydev0"); ... } 5 . 4
53. ADICIONANDO O DISPOSITIVO /DEV/MYDEV0 #include <linux/init.h> #include <linux/module.h> static struct class *mydev_class; static int my_init(void) { ... mydev_class = class_create(THIS_MODULE, DRV_NAME); device = device_create(mydev_class, NULL, mydev->id, NULL, "mydev0"); ... } 5 . 4
54. ADICIONANDO O DISPOSITIVO /DEV/MYDEV0 #include <linux/init.h> #include <linux/module.h> static struct class *mydev_class; static int my_init(void) { ... mydev_class = class_create(THIS_MODULE, DRV_NAME); device = device_create(mydev_class, NULL, mydev->id, NULL, "mydev0"); ... } 5 . 4
55. ADICIONANDO O DISPOSITIVO /DEV/MYDEV0 #include <linux/init.h> #include <linux/module.h> static struct class *mydev_class; static int my_init(void) { ... mydev_class = class_create(THIS_MODULE, DRV_NAME); device = device_create(mydev_class, NULL, mydev->id, NULL, "mydev0"); ... } static void my_exit(void) { ... device_destroy(mydev_class, mydev->id); class_destroy(mydev_class); ... } 5 . 4
56. ADICIONANDO O DISPOSITIVO /DEV/MYDEV0 #include <linux/init.h> #include <linux/module.h> static struct class *mydev_class; static int my_init(void) { ... mydev_class = class_create(THIS_MODULE, DRV_NAME); device = device_create(mydev_class, NULL, mydev->id, NULL, "mydev0"); ... } static void my_exit(void) { ... device_destroy(mydev_class, mydev->id); class_destroy(mydev_class); ... } 5 . 4
57. ADICIONANDO O DISPOSITIVO /DEV/MYDEV0 #include <linux/init.h> #include <linux/module.h> static struct class *mydev_class; static int my_init(void) { ... mydev_class = class_create(THIS_MODULE, DRV_NAME); device = device_create(mydev_class, NULL, mydev->id, NULL, "mydev0"); ... } static void my_exit(void) { ... device_destroy(mydev_class, mydev->id); class_destroy(mydev_class); ... } 5 . 4
58. INICIALIZAÇÃO E REGISTRO DO DEVICE DRIVER #include <linux/init.h> #include <linux/module.h> #include <linux/fs.h> static int my_init(void) { ... ret = alloc_chrdev_region(&mydev->id, minor, num_devs, DRV_NAME); ... cdev_init(&mydev->cdev, &mydev_fops); mydev->cdev.owner = THIS_MODULE; mydev->cdev.ops = &mydev_fops; ... ret = cdev_add(&mydev->cdev, mydev->id, num_dev); ... } module_init(my_init); 5 . 5
59. INICIALIZAÇÃO E REGISTRO DO DEVICE DRIVER #include <linux/init.h> #include <linux/module.h> #include <linux/fs.h> static int my_init(void) { ... ret = alloc_chrdev_region(&mydev->id, minor, num_devs, DRV_NAME); ... cdev_init(&mydev->cdev, &mydev_fops); mydev->cdev.owner = THIS_MODULE; mydev->cdev.ops = &mydev_fops; ... ret = cdev_add(&mydev->cdev, mydev->id, num_dev); ... } module_init(my_init); 5 . 5
60. INICIALIZAÇÃO E REGISTRO DO DEVICE DRIVER #include <linux/init.h> #include <linux/module.h> #include <linux/fs.h> static int my_init(void) { ... ret = alloc_chrdev_region(&mydev->id, minor, num_devs, DRV_NAME); ... cdev_init(&mydev->cdev, &mydev_fops); mydev->cdev.owner = THIS_MODULE; mydev->cdev.ops = &mydev_fops; ... ret = cdev_add(&mydev->cdev, mydev->id, num_dev); ... } module_init(my_init); 5 . 5
61. INICIALIZAÇÃO E REGISTRO DO DEVICE DRIVER #include <linux/init.h> #include <linux/module.h> #include <linux/fs.h> static int my_init(void) { ... ret = alloc_chrdev_region(&mydev->id, minor, num_devs, DRV_NAME); ... cdev_init(&mydev->cdev, &mydev_fops); mydev->cdev.owner = THIS_MODULE; mydev->cdev.ops = &mydev_fops; ... ret = cdev_add(&mydev->cdev, mydev->id, num_dev); ... } module_init(my_init); 5 . 5
62. INICIALIZAÇÃO E REGISTRO DO DEVICE DRIVER #include <linux/init.h> #include <linux/module.h> #include <linux/fs.h> static int my_init(void) { ... ret = alloc_chrdev_region(&mydev->id, minor, num_devs, DRV_NAME); ... cdev_init(&mydev->cdev, &mydev_fops); mydev->cdev.owner = THIS_MODULE; mydev->cdev.ops = &mydev_fops; ... ret = cdev_add(&mydev->cdev, mydev->id, num_dev); ... } module_init(my_init); 5 . 5
63. FINALIZAÇÃO E LIMPEZA #include <linux/init.h> #include <linux/module.h> static void my_exit(void) { ... cdev_del(&mydev->cdev); unregister_chrdev_region(mydev->id, num_devs); ... } module_exit(my_exit); 5 . 6
64. FINALIZAÇÃO E LIMPEZA #include <linux/init.h> #include <linux/module.h> static void my_exit(void) { ... cdev_del(&mydev->cdev); unregister_chrdev_region(mydev->id, num_devs); ... } module_exit(my_exit); 5 . 6
65. FINALIZAÇÃO E LIMPEZA #include <linux/init.h> #include <linux/module.h> static void my_exit(void) { ... cdev_del(&mydev->cdev); unregister_chrdev_region(mydev->id, num_devs); ... } module_exit(my_exit); 5 . 6
66. RECAPITULANDO 6 . 1
67. UTILIZAÇÃO import RPi.GPIO as gpio gpio.output(led_pin, gpio.HIGH) 6 . 2
68. UTILIZAÇÃO OU import RPi.GPIO as gpio gpio.output(led_pin, gpio.HIGH) if ((fd = fopen("/sys/class/gpio/gpio23/value", "w")) != NULL) { fwrite("1", sizeof(char), 2, fd); fclose(fd); } 6 . 2
69. UTILIZAÇÃO OU import RPi.GPIO as gpio gpio.output(led_pin, gpio.HIGH) if ((fd = fopen("/sys/class/gpio/gpio23/value", "w")) != NULL) { fwrite("1", sizeof(char), 2, fd); fclose(fd); } 6 . 2
70. UTILIZAÇÃO OU import RPi.GPIO as gpio gpio.output(led_pin, gpio.HIGH) if ((fd = fopen("/sys/class/gpio/gpio23/value", "w")) != NULL) { fwrite("1", sizeof(char), 2, fd); fclose(fd); } 6 . 2
71. MUITO OBRIGADO! QUESTÕES? 7