User Manual

MPU-9250 Register Map and Descriptions
Document Number: RM-MPU-9250A-00
Revision: 1.4
Release Date: 9/9/2013
BIT
NAME
FUNCTION
[6]
I2C_SLV0_BYTE_SW
1 – Swap bytes when reading both the low and high byte of a word.
Note there is nothing to swap after reading the first byte if
I2C_SLV0_REG[0] = 1, or if the last byte read has a register address
lsb = 0.
For example, if I2C_SLV0_REG = 0x1, and I2C_SLV0_LENG = 0x4:
1) The first byte read from address 0x1 will be stored at
EXT_SENS_DATA_00,
2) the second and third bytes will be read and swapped, so the
data read from address 0x2 will be stored at
EXT_SENS_DATA_02, and the data read from address 0x3
will be stored at EXT_SENS_DATA_01,
3) The last byte read from address 0x4 will be stored at
EXT_SENS_DATA_03
0 – no swapping occurs, bytes are written in order read.
[5]
I2C_SLV0_REG_DIS
When set, the transaction does not write a register value, it will only
read data, or write data
[4]
I2C_SLV0_GRP
External sensor data typically comes in as groups of two bytes. This
bit is used to determine if the groups are from the slave’s register
address 0 and 1, 2 and 3, etc.., or if the groups are address 1 and 2, 3
and 4, etc..
0 indicates slave register addresses 0 and 1 are grouped together (odd
numbered register ends the group). 1 indicates slave register
addresses 1 and 2 are grouped together (even numbered register ends
the group). This allows byte swapping of registers that are grouped
starting at any address.
[3:0]
I2C_SLV0_LENG[3:0]
Number of bytes to be read from I2C slave 0
4.14 Registers 40 to 42 – I
2
C Slave 1 Control
Register 40 - I2C_SLV1_ADDR
Serial IF: R/W
Reset value: 0x00
BIT
NAME
FUNCTION
[7]
I2C_SLV1_RNW
1 – Transfer is a read
0 – Transfer is a write
[6:0]
I2C_ID_1[6:0]
Physical address of I2C slave 1
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