User's Manual l MBa8Xx UM 0100 l © 2020, TQ-Systems GmbH
Page 14
3.3.2
M4 I
2
C interface
In addition to the I²C interfaces I2C1 and I2C2, the interface of the i.MX 8X system controller is also available on the MBa8Xx.
The M4_I2C bus is connected to header X5. There are no other devices on this bus on the MBa8Xx.
Both I²C lines M4_I2C_SCL and M4_I2C_SDA are provided with 2.2-kΩ pull-up resistors to 1.8 V on the MBa8Xx.
To reduce the bus load on I2C1, the I²C devices on the MBa8Xx can be connected to the I2C2 bus. As shown in the following
table, the configuration of the used I²C bus is determined by the resistors R371 to R374.
Table 11:
Assembly option I2C1 / I2C2 bus for I²C devices on MBa8Xx
I²C bus
R371
R372
R373
R374
Remark
I2C1
0 Ω
0 Ω
NP
NP
Default
I2C2
NP
NP
0 Ω
0 Ω
–
In addition to the pull-up resistors on the I2C1 bus on the TQMa8Xx, the bus load can be adapted on the MBa8Xx by assembling
further pull-up resistors (R266 on SCL, R267 on SDA).
3.3.3
Further I
2
C devices
In addition to the port expander and the temperature sensor, more I
2
C devices are connected to the I2C1, see Table 10.
These devices are described in the respective chapter for the corresponding interface.
