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Jseyn.1
Jseyn.1
Associate III
January 10, 2022
Question

STM32F1xx smbus send address no ack?

  • January 10, 2022
  • 6 replies
  • 1835 views

my smbus device is a temperature sensor (TMP100).MCU is STM32F103RBT6

when i wrote a word to slave as following:

I2C_GenerateSTART(SMBus_NAME, ENABLE);

while(!I2C_CheckEvent(I2C2,I2C_

I2C_Send7bitAddress(SMBus_NAME, slaveAddr, I2C_Direction_Transmitter);

while(!I2C_CheckEvent(I2C2,I2C_EVENT_MASTER_TRANSMITTER_MODE_SELECTED)){;}

I2C_SendData(I2C2,addr);// device registor address

the registor I2C2->SR1 : 0x4400. due to the smbus line nack.. how to solve it?

This topic has been closed for replies.

6 replies

Bubbles
Bubbles
ST Employee
January 10, 2022

Hi, what is the configured bus speed?

Do you have a scope to observe the SMBUS line?

The nack can be anything, best if you can use a scope or at least logic analyzer to observe.

BR,

J

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TDK
TDK
January 10, 2022

If the slave does not ACK, there is likely a hardware issue and/or you are using the incorrect slave address. Your code doesn't contain enough information to determine the latter. Note that slave addresses should be left-aligned.

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Tesla DeLorean
Tesla DeLorean
Guru
January 10, 2022

https://www.ti.com/lit/ds/symlink/tmp100.pdf?ts=1641822742177

Slave Address (Table 2)

1001000 -> 0x90

1001001 -> 0x92

1001010 -> 0x94

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Jseyn.1
Jseyn.1Author
Associate III
January 11, 2022

0693W00000HrAyPQAV.pngI recheck my slave address 0x48, as TDK said the slave address left-aligned(0x90). smbus clock is 100khz. I2C_SendData(I2C2,addr) failed, the smbdata line sholud be low,but no changes.

Jseyn.1
Jseyn.1Author
Associate III
January 25, 2022

hi ,

about the SMBus Alert response , gotta dizzy. could u tell the timing? as the smbhost send 0x18 or 0x19 gotta no ack

0693W00000JNBqyQAH.png 

Jseyn.1
Jseyn.1Author
Associate III
January 26, 2022

Hey,

Thankyou for the slience, i gotta it.

smhost to request the slave addres & status when the alert pin active.

0693W00000JNKN2QAP.png

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