One of the security features offered by the LPC55S6x is Secure GPIO. In the user manual is it given some insights about its configuration. Meanwhile, I was not able to see what this "type" of GPIO is additionally adding comparing to the "causal" GPIO. What do Secure mean in this context?
Thank you in advance.
Due to the architecture of normal GPIO, all digital IO pins states are readable through normal GPIO module from the GPIO read path, independent of which function is chosen for this pin(UART,SPI,I2C,etc). As a result, there is a possibility of leaking information from secure resource.
The application note for secure gpio will provide the details of what it entails such as the secure gpio mask that is implemented in order to turn on and off the state of this peripheral.
Hope this helps.
Have a great day!