Emblinux

Emblinux DC-MOTOR

利用tftp把host和target連接 • Run kernel • Run rootfs

拷貝driver到linux中 • 用make得到ko檔(驅動) • 在用/usr/local/arm/3.4.1/bin/arm-linux-gcc –o xx_test xx_test.c可得xx_test(測試檔)

Dc motor • 如同pwm一樣用duty cycle控制轉速 • 程式如下(在附件) dc_motor.c dc_motor_test.c

PWM and timer in Samsung S3C2410X TCMPB0 TCNTB0 PWM 0 TOUT0 Control Logic 0 Dead zones generator 1/16 1/32 1/64 1/128 TCLK0 Dead Zone PCLK 8-bit prescaler TCMPB1 TCNTB1 TOUT1 PWM 1 TCMPB2 TCNTB2 Dead Zone PWM 2 TOUT2 • TCNTB: Time counter buffer register for clock period • TCMPB: Time compare buffer register for PWM pulse width TCMPB3 TCNTB3 1/16 1/32 1/64 1/128 TCLK0 PWM 3 TOUT3 8-bit prescaler TCNTB4 Control Logic 4 No pin

Pulse-width modulation (PWM) • DC motor control: Rotation speed proportional to input voltage level • DC-to-DC converter • Digital-to-analog converter • PWM (use average voltage) • Use pulse width as control command to output device 5V Duty cycle Average value Pulse width μP 25% 1.25 PWM 50% 2.5 75% 3.75

DC motor connection

GPIO registers

set_pwm3函數：完成對直流馬達的脈波比調節。參數hiratio為占空百分比（0~100） static void set_pwm3(unsigned char hiratio) { unsigned long tcnt; printk("hiratio = %d",hiratio); tcnt =( 96000000 )/( FREQ_PWM1 *16 ); __raw_writel(((tcnt*(hiratio))/100), S3C2410_TCMPB(3)); }

dcm_ioctl函數：透過呼叫set_pwm3函數，傳送不同的脈波比參數，對直流馬達的速度進行10級調節 static int dcm_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { switch(cmd) { case DC_IOCTL_START: set_pwm3(DUTY); break; case DC_IOCTL_STOP: set_pwm3(0); printk("off\n"); break; case DC_IOCTL_SPEED_UP: DUTY +=STEP; if (DUTY>MAX_VAL) DUTY=MAX_VAL; set_pwm3(DUTY); break; case DC_IOCTL_SPEED_DOWN: DUTY -=STEP; if (DUTY<0) DUTY=0; set_pwm3(DUTY); printk("PWM_IOCTL_SPEED_DOWN\n"); break; default : break; } return 0; }

對dcm_ioctl的參數初始化 • #define MAX_VAL 90 • static int DUTY = 50; • static int STEP=10;

作業 • 不要透過uart而改變馬達轉速(DUTY:0~100)

Emblinux

Emblinux

Presentation Transcript