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stm32f103, i2c, bit start ignored if not set bit ACK ??

according to the documentation for the iic bus, devices must create start conditions, even if the devices ignore the ACK bit, but stm32f103, in fact, ignores the start bit without the ACK bit.

if this is not the case, then where is it written in the iic documentation that the start conditions should not be formed if someone on the bus knows in advance that the ak bit will be ignored?

ST Employee


it's difficult to understand what you meant. Master initiates communication using start condition. Then if address matches, the slave device should ACK. The STM32 follows this principle. Ignoring start bit is a possibility, then the slave device is practically deaf.



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without any slaves, the master must first issue at least 1 byte, and only then discover that there are no slaves, but without the ASK bit, the master does not even create starting conditions, and the offset then pulls both lines synchronously down.