We always say that the pcDuino is compatible with arduino platform, but there are some different in some part, here I will introduce the different of GPIO between the pcDuino and arduino and what we should pay attention to in a normal application.
1.The difference between input and output:The arduino platform are generally AVR singlechip computer of the atmel company, the GPIO of this singlechip computer is 5V withstand voltage, so UART interface can bear 5V voltage. The GPIO of pcDuino is 3.3 V withstand voltage so as to the UART. We must check the signal level whether it is compatible when use the serial communication, or it will lead to the damage of the main control chip.
2.Flip speed problems: Because AVR microcontroller CPU frequency is only up to 16MHZ, so gpio flip speed is basically consistent with the CPU speed, but the CPU frequency of pcduino is up1GHZ, and this time the flip speed GPIO can also impossible keep up with the CPU, pcduino the GPIO is unlikely to exceed the maximum turning speed of APH clock A10, A10’s largest APB clock is 136MHZ. So we do not mistakenly believe the speed GPIO can flip to GHZ.
3.The pin functions reuse question: What is pin reuse functions? This is in addition to first function, it adds more function such as the 89C51 SCM P3 I/O ports and also for the interrupt pin, mainly for saving the chip resource. AVR platform arduino function reuse is mainly reflected in the ADC, UART, SPI, PWM, I2C and other functional modules, the ADC interface can also be used as an analog signal input as well as ordinary GPIO, these pins are distribute on arduino A0-A5, however the pcDuino A0-A5 can’t be used as GPIO. So do not connect the control signals to pcDuino A0-A5 when you do this experiment..