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 ...

in RM0008 Rev 21page 775Bits 5:0 FREQ[5:0]: Peripheral clock frequencythe description of the frequency divider is extremely unclear. there is no formula for where the input is, how it is divided, where the output is. what if I want to set strictly 50...

PM0056, Rev 6, page 91, Table 30. Branch and control instructionsCBNZ     Compare and Branch if Non ZeroCBZ     Compare and Branch if Non Zeroreally ?but later :3.8.6  CBZ and CBNZCompare and branch on zero, compare and branch on non-zero.