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电池计量芯片I2C通讯地址冲突

Fei xu
Prodigy 100 points
Other Parts Discussed in Thread: BQ27Z561, EV2400, BQ28Z610, TCA9543A, SN74AUP1G04, SN74AUP1G32, SN74LVC1G3157

Hi

我有一块BQ28Z610 和一块 BQ27Z561 的EVM板，BQ27Z561 的EVM板上有EV2400 与其通信。 我的问题是这两个计量芯片的I2C地址都是一样的，如果将一颗EV2400 芯片同时连上两块计量芯片就会发生地址冲突完全不通信的情况。

有没有什么办法disable 掉其中一块芯片的I2C通信或者改掉其I2C地址呢？我在手册中看到I2C地址是只读的。

在具体的电池包应用中，苹果的电池级联的电池包里有用两块计量芯片，是怎么解决掉通信冲突的问题？ 

谢谢回复

  • 0
    TI__Guru*** 130456 points
    您可以用i2c multiplexer
    Here are a few options to get around the duplicate I2C device address issue:
    a) If your processor has a second I2C interface, it can be used to control the second gauge on a separate bus.
    b) If you don’t have an extra GPIO and only have one I2C interface, you could use one of our I2C port expanders. The TCA9543A is a great two channel device for such a project.

    TCA9543A: 2-Channel I2C Bus Switch With Interrupt Logic and Reset
    Product Folder: www.ti.com/.../TCA9543A
    Datasheet (PDF): www.ti.com/.../scps206a

    c) You can use a GPIO to effectively route SCL to only one of the devices at a time.
    One way to implement this is with an inverter for the control signal and a dual OR gate to route SCL.
    1. Connect SCL from your processor to one of the inputs of each OR gate, A pull up resistor must be located on this node (2kOhm is ok).
    2. Connect the non-inverted control signal to the other input of the first OR gate.
    3. Connect the inverted control signal to the other input of the second OR gate.
    4. Connect the first OR gate's output to SCL on the first gauge(A) and the second OR gate's output to SCL on the second gauge(B).
    5. When the GPIO is high, you will communicate with gauge(A) and when it is low, you will communicate with gauge(B).

    SN74AUP1G04: Low-Power Single Inverter Gate

    Product Folder: www.ti.com/.../SN74AUP1G04

    Datasheet (PDF): www.ti.com/.../sces571k

    SN74AUP1G32: Low-Power Single 2-Input Positive-OR Gate

    Product Folder: www.ti.com/.../SN74AUP1G32

    Datasheet (PDF): www.ti.com/.../sces580i

    d) You can also use an SPDT switch to route the SCL signal to each of the devices. The LVC1G3157 is a great fit for this.

    SN74LVC1G3157: Single-Pole, Double-Throw Analog Switch

    Product Folder: www.ti.com/.../SN74LVC1G3157

    Datasheet (PDF): www.ti.com/.../sn74lvc1g3157