GPIO-Usage-&-Used-Pins.md

@@ -4,7 +4,7 @@ GPIOs are grouped in ports and so each GPIO has an identifier.
 The identifiers have the following format: `PXY`, where `X` is the GPIO port name and `Y` is the pin number.
 
 ## Introduction
-GPIO ports registers are mapped to well defined memory addresses. This means that by accessing those addresses, we can access the GPIO registers.  
+GPIO ports' registers are mapped to well defined memory addresses. This means that by accessing those addresses, we can access the GPIO registers.  
 Then, we can define a structure that represents the memory layout of the GPIO registers:
 ```cpp
 typedef struct
@@ -23,14 +23,14 @@ typedef struct
 ```
 Remmeber that strcut member's are allocated to consecutive addresses in memory.  
   
-In order to access a specific register (address) we need a pointer to the GPIO port.  
+In order to access a specific register (address) we need a pointer to a `GPIO_TypeDef` structure.  
 Assuming we want to control the `GPIOA` port and that it can be found at `0x48000000`: 
 ```cpp
 #define GPIOA ((GPIO_TypeDef *) 0x48000000)
 ```
-By simply changing the pointer address we can access different GPIO ports.  
+By simply changing the pointer address we can access to different GPIO ports.  
   
-Via *bitwise operations* we can access the GPIO registers:
+Via *bitwise operations* we can modify single bits of the GPIO registers:
 ```cpp
 // set 5th bit of ODR to 1
 GPIOA->ODR |= (1 << 4);