Data Sheet

Sensors
Freescale Semiconductor 17
MMA8452Q
Multiple Byte Write
The MMA8452Q 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
MMA8452Q acknowledgment (ACK) is received.
Figure 12. I
2
C Timing Diagram
Table 10. I
2
C Device Address Sequence
Command
[6:1]
Device Address
[0]
SA0
[6:0]
Device Address
R/W 8-bit Final Value
Read 001110 0 0x1C 1 0x39
Write 001110 0 0x1C 0 0x38
Read 001110 1 0x1D 1 0x3B
Write 001110 1 0x1D 0 0x3A
< Single Byte Read >
Master
ST Device Address[6:0] W Register Address[7:0] SR Device Address[6:0] R NAK SP
Slave
AK AK AK Data[7:0]
< Multiple Byte Read >
Master
ST Device Address[6:0] W Register Address[7:0] SR Device Address[6:0] R AK
Slave
AK AK AK Data[7:0]
Master
AK AK NAK SP
Slave
Data[7:0] Data[7:0] Data[7:0]
< Single Byte Write >
Master
ST Device Address[6:0] W Register Address[7:0] Data[7:0] SP
Slave
AK AK AK
< Multiple Byte Write >
Master
ST Device Address[6:0] W Register Address[7:0] Data[7:0] Data[7:0] SP
Slave
AK AK AK AK
Legend
ST: Start Condition SP: Stop Condition NAK: No Acknowledge W: Write = 0
SR: Repeated Start Condition AK: Acknowledge R: Read = 1