Sensors

Freescale Semiconductor

17

MMA7455L

SINGLE BYTE WRITE

To start a write command, the Master transmits a start condition (ST) to the MMA7455L, slave address ($1D) with the R/W bit set

to “0” for a write, the MMA7455L sends an acknowledgement. Then the Master (MCU) transmits the 8-bit address of the register

to write to, and the MMA7455L sends an acknowledgement. Then the Master (or MCU) transmits the 8-bit data to write to the

designated register and the MMA7455L sends an acknowledgement that it has received the data. Since this transmission is com-

plete, the Master transmits a stop condition (SP) to the data transfer. The data sent to the MMA7455L is now stored in the ap-

propriate register. See Figure 9.

Figure 7. Single Byte Read - The Master is reading one address from the MMA7455L

Figure 8. Multiple Bytes Read - The Master is reading multiple sequential registers from the MMA7455L

Figure 9. Single Byte Write - The Master (MCU) is writing to a single register of the MMA7455L

MULTIPLE BYTES WRITE

The MMA7455L automatically increments the received register address commands after a write command is received. Therefore,

after following the steps of a single byte write, multiple bytes of data can be written to sequential registers after each MMA7455L

acknowledgment (ACK) is received. See Figure 10.

Figure 10. Multiple Byte Writes - The Master (MCU) is writing to multiple sequential registers of the MMA7455L