Am I right in thinking that all the GPIO pins are 3.3V tolerant, but not 5V tolerant?
If so, isn't the 5V GPIO inviting a lot of trouble?
For example, the blinkt uses the 5V pin. How comes it doesn't cause damage to the other pins that it uses for SPI communication? Does the blinkt have a built-in voltage divider for example?
Or it is that the voltage on the SPI lines is pulled up to 3.3V by the Pi, which is then only ever grounded?
It seems that there are lots of opportunities to fry you pins if you try to connect two devices together for the purposes of communication over, say, SPI or I2C. And how do you work out what the line voltage is