2012-07-22 03:21 AM
I have been building my own Boards.
And have experience with an assortment of Micros. WARNING #1 : I have found that these STM Chips are Very SENSITIVE to Voltages. I accidentally tied the USB 5V source to the VDD Bus thinking that it could also Power the Chip - accidentally for a few Seconds. Now the STM32 Chip and Board are USELESS. Do NOT use ANY Voltage HIGHER than 3.5V on ANY Pin to the STM32 Micros -or the Chip becomes ABSOLUTELY USELESS. Flash Programs will Not Execute -and the Programmer will Not recognize the STM Chip anymore. The other chips, atm for example, are not so Sensitive. And, I never encountered issues with brief stray Voltage Levels. All I can say is Be Careful as can be. And if you think that the STM is Not responding to the Programmer - then it is probably so - and a waste of time to try to resurrect the Chip. What threw me off is that the Stm32 Micros can Not be Directly powered off of the USB Bus (as I would at first assume). You need to place a VReg (like 3.3V) between them.2012-07-24 12:21 PM
''I don't know too many logic chips that the IO pin input voltages can be greatter than the chip's Vdd''
That's what they mean by, ''5V-tolerant''
''Which breaks your same rule from Spec''
The spec gives specific ratings for the 5V-tolerant pins
2012-07-24 02:53 PM