cortex M3S811 study notes-GPIO-INT

First of all, the general IO port. No matter what microcontroller you learn, the IO port is the most important and easiest to learn. It is important because it is the interface between the microcontroller and the peripheral device, and it is also what we usually call the human-machine interface. It is easy to learn because it is easy to control. It is nothing more than enabling the port, setting the direction, and then writing or reading data (depending on the direction you set). The IO port of this super powerful 32-bit ARM core is also different. After all, it is an ARM core, and the IO registers are also richer. Let's take a look at the functions related to the IO port.

1. In order, enable the IO port first. Only when it is enabled can it be used, so of course it is the first step.
SysCtlPeripheralEnable (SYSCTL_PERIPH_GPIOA)

This is the function to enable port A, that is, port A can be used, and its door is open to you.
Doesn't port A have 6 pins in physical characteristics? GPIOA represents those 6 pins.
So how many other general IO ports does M3 have? Just count them and you will know. If you want to use it, you must understand it well. PA 0-5 PB 0-7 PC 0-7 PD 0-7 PE 0-2 ========== Is there a pattern? It seems a bit messy. Look at it this way. 51 is like this, P0, P1, P2, P3 //
Here are PA, PB, PC, PD. What about PE, where does it come from? Because our PA only has 6 pins, so it gives its two pins to others (PE1, 2). Like 51, both have 32 pins.
Remember this, PA has six pins and PE has two pins. The two PE pins can also be used as motors (because its second function is pwm4, pwm5).

Needless to say, the other pins are 8 for power and ground, reset, two for crystal oscillator, and LD0 for voltage regulator. This is a total of 44 pins, and the remaining four pins are AD interfaces AD0-AD3. Just now, the port was enabled, and the port became active and can be used, but the function word is too long and I can't remember it. What should I do? Just make a macro definition, make one that I know.
#define DEVICEEN SysCtlPeripheralEnable
enables the device, and that's it.

What is the second step? What do you want to do? The most common thing is, are you going to connect a button (input) or an LED (output)?
Yes, it is to set the direction, there are three directions.
void GPIOPinTypeGPIOInpu (unsigned long ulPort, unsigned char ucPins)
void GPIOPinTypeGPIOOutput (unsigned long ulPort, unsigned char ucPins)
ulPort is which port, ucPins is which pin or pins
The function name is too long, so it is better to make a macro definition that you are familiar with
#define GPIOIN GPIOPinTypeGPIOInpu
#define GPIOOUT GPIOPinTypeGPIOOutput
Now let's take an example: set the 0th pin of PA as output and the second pin as input.

GPIOOUT (GPIO_PORTA_BASE, GPIO_PIN_0)
GPIOIN (GPIO_PORTA_BASE, GPIO_PIN_2)

Of course, I still think that GPIO_PORTA_BASE, GPIO_PIN_2 are too long.
After all, they are things that we need to deal with frequently. I will make a macro definition:
#define PA GPIO_PORTA_BASE
#define PIN2 GPIO_PIN_2

Then the above statement becomes, GPIOIN (PA, PIN2);
which feels a lot clearer (Note: you must remember the macros you defined)


In the third step, the direction is also set, so all that’s left is reading and writing numbers.
void GPIOPinWrite(unsigned long ulPort, unsigned char ucPins, unsigned char ucVal);
long GPIOPinRead(unsigned long ulPort, unsigned char ucPins)

Then macro definition:
#define WRITE GPIOPinWrite
#define READ GPIOPinRead

Now you can turn on the light. If your PA0 is connected to an LED (cathode is grounded),
you only need this statement to light it up: WRITE(PA,PIN0,1);