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
[7]
I2C_SLV3_EN
1 – Enable reading data from this slave at the sample rate and storing data
at the first available EXT_SENS_DATA register as determined by
I2C_SLV0_EN, I2C_SLV0_LENG, I2C_SLV1_EN, I2C_SLV1_LENG,
I2C_SLV2_EN and I2C_SLV2_LENG.
0 – function is disabled for this slave
[6]
I2C_SLV3_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_SLV3_REG[0] = 1,
or if the last byte read has a register address lsb = 0.
See I2C_SLV1_CTRL for an example.
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_SLV3_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_SLV3_LENG[3:0]
Number of bytes to be read from I2C slave 3
4.17 Registers 49 to 53 – I
2
C Slave 4 Control
Register 49 - I2C_SLV4_ADDR
Serial IF: R/W
Reset value: 0x00
BIT
NAME
FUNCTION
[7]
I2C_SLV4_RNW
1 – Transfer is a read
0 – Transfer is a write
[6:0]
I2C_ID_4[6:0]
Physical address of I2C slave 4
Register 50 - I2C_SLV4_REG
Serial IF: R/W
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