Hardware design: List of sensitive GPIO pins, pins which need special care

[flyer31]

Posted on January 16, 2012 at 12:47

Hi,

could you perhaps help me to create a list of GPIO pins, which need some special care during the hardware design? I think some people reported already some problems with a JTAG pin, if used as output, and I think somewhere also I read, that some USB-FS-PHY pins may have some restrictions if used as outputs. But I do not get it together from my remembering, where I read this. If some people could share their pin-precautions/ -warnings, best for the STM32F4 parts, that would be great.

[flyer31]

Posted on January 16, 2012 at 16:27

I just found again the text concerning the 4 general pins - it did not concern USB-FS-PHY pins, but instead the RTC pins:

[see STM32F415xx, STM32F417xx datasheet page 49/156 (At the end of table 5, footnote 3)]: ''PC13, PC14, PC15 and PI8 are supplied through the power switch. Since the switch only sinks a limited amount of current (3 mA), the use of GPIOs PC13 to PC15 and PI8 in output mode is limited: the speed should not exceed 2 MHz with a maximum load of 30 pF and these I/Os must not be used as a current source (e.g. to drive an LED).'' PC13,PC14,PC15 are available in any housing, PI8 only in the 176 pin versions.