PWM fifo,bus flag error - Raspberry Pi Forums

hello everybody,

i'm trying configure gpio18 pwm0 output. did following configurations

highlight:

code: select all

  gpf_sel1_v = 0x2000000; //set gpio18 alt5 -> pwm   pwm_ctl_v = pwm0_enable | pwm0_ms_mode;   pwm_rng1_v = 0x400;   pwm_dat1_v = 0x300; //duty cycle of 75% 

more code:

code: select all

//definities van de registers  #define gpf_sel1   	0x20200004    #define gpf_sel1_v      (*(volatile unsigned long *)gpfsel1)      #define pwm_ctl  	0x2020c000   				 #define pwm_ctl_v      (*(volatile unsigned long *)pwmctl)  #define pwm_sta  	0x2020c004   				 #define pwm_sta_v      (*(volatile unsigned long *)pwmsta)  #define pwm_rng1  	0x2020c010  				 #define pwm_rng1_v      (*(volatile unsigned long *)pwmrng1)  #define pwm_dat1  	0x2020c014   				 #define pwm_dat1_v      (*(volatile unsigned long *)pwmdat1)  #define	pwmclk_cntl	40 #define	pwmclk_div	41 #define	pwm0_ms_mode    0x0080  // run in ms mode #define	pwm0_usefifo    0x0020  // data fifo #define	pwm0_revpolar   0x0010  // reverse polarity #define	pwm0_offstate   0x0008  // ouput off state #define	pwm0_repeatff   0x0004  // repeat last value if fifo empty #define	pwm0_serial     0x0002  // run in serial mode #define	pwm0_enable     0x0001  // channel enable   #define module_name "pwm_module"   unsigned long gpfsel1;  unsigned long gpset0;  unsigned long gpclr0; unsigned long pwmctl; unsigned long pwmrng1; unsigned long pwmdat1; unsigned long pwmsta; unsigned long value;  ...  int pb_init(void)  { ...    printk("<1>pb: ioremap\n");     gpfsel1 =(unsigned long)ioremap(gpf_sel1,4); 	   gpset0 =(unsigned long)ioremap(gp_set0,4);    gpclr0 =(unsigned long)ioremap(gp_clr0,4);    pwmctl =(unsigned long)ioremap(pwm_ctl,4);    pwmrng1 =(unsigned long)ioremap(pwm_rng1,4);   pwmdat1 =(unsigned long)ioremap(pwm_dat1,4);   pwmsta =(unsigned long)ioremap(pwm_sta,4); 		     printk("<1>pb set register\n");  				     gpf_sel1_v = 0x2000000; //set gpio18 alt5 -> pwm   pwm_ctl_v = pwm0_enable | pwm0_ms_mode;   pwm_rng1_v = 0x400;   pwm_dat1_v = 0x300; //duty cycle of 75%    value = pwm_sta_v;   printk("%ld",value);      return 0;  }  ...   module_init(pb_init); 					 module_exit(pb_exit);						 

when read pwm status register flag "fifo read error flag" , "bus error flag" high. don't use fifo instead use data register. know i'm doing wrong?

thanks

most of code i've seen sprinkles 10 microsecond delays around writing pwm registers.

raspberrypi