hello everyone,I'm still a chinese student,now I use freescale's product MMa8451q using IIC comunication mode,so I choose MC9s08AW60's iic model to control it ,but it can't work rightly,hurting me.
so much word,I will give my code to let any friend point out potential mistake.
#include <hidef.h> /* for EnableInterrupts macro */#include "derivative.h" /* include peripheral declarations */#include "clock_delay.h"#include "sci.h"#define turn_on_buzzer PTADD_PTADD1=1;PTAD_PTAD1=1#define shut_down_buzzer PTAD_PTAD1=0#define iic_start IIC1C_MST=1#define iic_stop IIC1C_MST=0#define iic_restart IIC1C_RSTA=1#define iic_acknowledge IIC1C_TXAK=0void iic_send(unsigned char data){ IIC1C|=0x30; IIC1D=data; while(!IIC1S_TCF); /////////waiting for send complete while(IIC1S_RXAK); ///////////waiting for the ack from the slave }unsigned char iic_read(void){ unsigned char temp; IIC1C_TX=0; temp=IIC1D; while(!IIC1S_TCF); /////////waiting for send complete return(IIC1D); }///////the mainvoid main(void) { unsigned int i=10,n; n=4; clock_init(); /////////////*seting 20Mhz bus clock; sci_init(); //IIC1F=0b00011101; ///////////////MULT=00, ICR=0x1d IIC1F=0x1f; ////////////////////*according to my calculating,this can get 1.65us sda hold time,but I can't sure if it's appropriate for mma8451q //IIC1F=0x14; IIC1C_IICEN=1; IIC1C_IICIE=0; IIC1C_TXAK=1; EnableInterrupts; /* enable interrupts */ turn_on_buzzer; delay_nms(100); shut_down_buzzer; while(1) { IIC1C_IICEN=1; iic_send(0x38); /////////////// give the write commend iic_send(0x0d); /////////////////////provide the address of register iic_restart; ///////////////////////restart for reading iic_send(0x39); //////////////////give the read commend i=iic_read(); iic_stop; IIC1C_IICEN=0; /////////*if I don't clear this bit, this function can only circulate one circle,I don't know why,if I clear it,this while function can circulate,but I can only get i=0,meaning 8451q only return 0;This is another confusion!!! five_digit_uart(i); ///////*using sci to see it's value,the sci has no problem I promised sci_send('\n'); turn_on_buzzer; delay_nms(100); shut_down_buzzer; delay_nms(1000); } } now I do some illustrate:In my code , I use 20M bus clock;
IIC1F=0x1f; ////////////////////*according to my calculating,this can get 1.65us sda hold time,but I can't sure if it's appropriate for mma8451q
IIC1C_IICEN=0; /////////*if I don't clear this bit, this function can only circulate one circle,I don't know why,if I clear it,this while function can circulate,but I can only get i=0,meaning 8451q only return 0;This is another confusion!!!
waiting for help…………
