What pins are used for I2C bootloader on the 20-pin STM32F070F6

[JBartz]

I cannot figure out which pins to connect to I2C on the STM32F070F6T6 chip.  AN2606 says to use PB6/PB7 which do not exist on this part.  The only pins that are mapped to I2C1 are PA9/PA10 or PF0/PF1 according the data sheet.  My first spin of a board uses PF0/PF1 and that does not appear to be working.

[STTwo-32]

Hello @JBartz and welcome to the ST Community.

If the Pins PB7/PB6 are not available on the package that you are using, then you can not use the Bootloader on the I2C for this particular package. But, you still can use the Open Bootloader. More details on that can be found on this FAQ. 
PS: don’t forget to check the links shared on the references on the FAQ.

Best Regards.

STTwo32

[JBartz]

Thanks much!  Next rev I'll move to the STM32F070C6 part which has those pins.

[TDK]

AN2606 lists all of the pins supported by the bootloader. In this case, as you saw, PB6/PB7 are the only I2C pins supported. Unfortunately, because they are not broken out on your chip, you won't be able to use the I2C bootloader here.

 

PA9/PA10 could be used with UART.