i2c - 什么是通用调用地址以及它在 I2C 中的用途是什么？

Question

我想知道 I2C (0x00) 中的广播地址是什么。如果我们有一个主站和一些从站，我们可以通过这个地址通过我们的主站与这些从站通信吗？

Answer 1

I2C 规范 v.6 ( https://www.i2c-bus.org/specification/ ) 的第 3.2.10 节清楚地描述了通用调用的目的。

3.2.10General call address

The general call address is for addressing every device connected to the I2C-bus at the same time. However, if a device does not need any of the data supplied within the general call structure, it can ignore this address. If a device does require data from a general call address, it behaves as a slave-receiver. The master does not actually know how many devices are responsive to the general call. The second and following bytes are received by every slave-receiver capable of handling this data. A slave that cannot process one of these bytes must ignore it. The meaning of the general call address is always specified in the second byte (see Figure 30).

您可以使用它来与您的从站通信，但有三个限制。

一般调用只能向slave写数据，不能读。

每个slave都应该收到general call，你不能用它来寻址特定的设备，或者你必须在general call消息体中编码设备地址，然后在slave中解码。

有标准的通用调用消息格式。您不应该为自己的功能使用标准代码。