vybrid MMA8451q

[lizhenq]

Hi,I am using the TWRVF65GS10 with MQX 4.1.But I finded no demo for MMA8451q.I try some times with Re: I2C Vybrid Code?.Vybrid can't get the ACK of MMA8451.I mant to get some surport ,documnet or code demo.

[Kan_Li · Accepted solution]

Hi Li Zhenq,

I just implemented an MQX I2C demo for MMA8451Q, it is for TWR-K60D100M, but should be easily ported to TWRVF65GS10, please kindly refer to [MQX 4.1]I2C demo for MMA8451Q for more details.

Hope that helps,

Have a great day,
Kan

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[lizhenq]

Thank you!!!

[lizhenq]

Hi Kan_Li,

   The VF6XX can send the IIC addr,but can't receive the ACK .I try addr 0X1C and 0X1D of MMA8451.The SCL is 8.4KHz.

[Kan_Li]

Hi Li Zhenq,

The I2C address for MMA8451Q on TWR-VF65GS10 should be 0x1C since SA0 is pulled down by R130 by default. Have you ported the demo to TWR-VF65GS10? Maybe you can share the printf messages for a review.

Thanks for your patience!!

Have a great day,
Kan

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[juangutierrez]

Hi

Here is some pseudocode for the initialization and sampling for the MMA8451Q

After initializing you should be able to read.

For the i2c_read and i2c_write, you can follow the implementation done for the mma7760 at <mqx_installation>/demo/accelerometer/accel_i2c.c

#define ADDR = 0x1C

typedef struct data {

     char reg

     char value

} data

Initialize_MMA8451Q {

     data.reg = 0x11 //PL_CFG

     data.val = 0xc0

     i2c_write(12c0, ADDR, data, sizeof(data))

     data_reg = 0x2a //CTRL_REG1

     data.val = 0x01

     i2c_write(12c0, ADDR, data, sizeof(data))

}

#define READ_DATA 0x01

#define READ_STATUS 0x10

sample_MMA8451Q {

  char x,y,z, status;

  char rcv_buf[6];

  i2c_read(12c0, ADDR, READ_DATA, rcv_buf, sizeof(rcv_buf));

  x = rcv_buf[0];

  y = rcv_buf[2];

  z = rcv_buf[4];

  i2c_read(12c0, ADDR, READ_STATUS, rcv_buf, 3);

  status = rcv_buf[0];

}

I will try to have get a sample version, probably by the end of next week.

[naoumgitnik]

Just clarification for those to reply to Li Zheng - MMA8451Q is Freescale Digital Accelerometer IC with an I2C interface (http://cache.freescale.com/files/sensors/doc/data_sheet/MMA8451Q.pdf).