SMBus与I2C的差别
The I²C bus and the SMBus are popular 2-wire buses that areessentially compatible with each other.
Below,significantdifferences between the two buses.
|
I²C |
SMBus |
Timeout |
No |
Yes |
Minimum Clock Speed |
DC |
10kHz |
Maximum Clock Speed |
100kHz (400kHz and 2MHz also available) |
100kHz |
VHIGH |
0.7 × VDD, 3.0V Fixed |
2.1V |
VLOW |
0.3 × VDD, 1.5V Fixed |
0.8V |
Max I |
3mA |
350µA |
Clock Nomenclature |
SCL |
SMBCLK |
Data Nomenclature |
SDA |
SMBDAT |
General Call |
Yes |
Yes |
Alert# |
No |
Yes |
SMBus与I2C的差别
SMBus与I2C总线之间在时序特性上存在一些差别。首先,SMBus需要一定数据保持时间,而 I2C总线则 是从内部延长数据保持时间。SMBus具有超时功能,因此当SCL太低而超过35 ms时,从器件将复位正在进行的通信。相反,I2C采用硬件复位。SMBus具有一种警报响应地址(ARA),因此当从器件产生一个中断时,它不会马上清 除中断,而是一直保持到其收到一个由主器件发送的含有其地址的ARA为止。SMBus只工作在从10kHz到最高100kHz。最低工作频率10kHz是由SMBus超时功能决定的
转载自:http://blog.csdn.net/sprewel3260334/article/details/50447614