STM32 SMBus Read Byte Error

[Ding Xiufang]

Posted on April 23, 2018 at 08:54

I used ST supply STM32_AN4502_FW_V2.0.2 for SMBus.When  test Read Byte command?0x19 can work?but 0x00 can not ACK right,TIMEOUT happen,Why?

#smbus

[waclawek.jan]

Posted on April 23, 2018 at 22:05

What is your hardware? How is it connected? Have you examined the SDA/SCL lines using an oscilloscope?

JW

[Ding Xiufang]

Posted on April 24, 2018 at 02:52

STM32F072RBT as slave, GUI as master. PMBus communication. When use GUI Read Byte (CMD=0x00), After Add_Rd byte have about 25ms delay then STOP, but use GUI Read Byte(CMD=0x19), All OK.

[waclawek.jan]

Posted on April 24, 2018 at 22:21

Have you examined the SDA/SCL lines using an oscilloscope?

JW

[Tesla DeLorean]

Posted on April 25, 2018 at 00:37

GUI? Do I have to read the app note to understand this? Try to paint a picture where I don't have to imagine the context and connectivity.

Perhaps the Slave doesn't understand/support certain things? If you don't understand whats happen inside the machine provide some diagnostic output via a serial or SWV connection, etc.