Rodrigo Almeida / pqdb

Pão de Queijo Development Board. This repo has all libraries from pqdb shield.

Dependents:   pqdb_demo

Pão de Queijo development board is a shield for add-on on any arduino compatible board.

/media/uploads/rmaalmeida/compatibilidade_branco.png

This project presents the libraries to control the board peripherals using mbed framework. The libraries works as interfaces to keep the main code compatible with the examples from the book "Programação de sistemas embarcados". The peripherals on the board are presented on the folowing picture

/media/uploads/rmaalmeida/pqdb_perifericos.png

The main objective of the project is to develop a low cost, easy to assemble board with a group of peripheral that allows one to start learning embedded systems. The board was routed on one side copper PCB to make easier to buid it yourself.

/media/uploads/rmaalmeida/pqdb_fenolite_-_cortada.png

The source code for Arduino boards (wiring) can be found on: https://github.com/projetopqdb/PQDB-Arduino

The source code for freedom frdm KL05 board (using direct register access) can be found on: https://github.com/projetopqdb/PQDB-KL05Z

The source code from the board schematics and layout can be found on: https://github.com/projetopqdb/PQDB-Hardware

kernel.cpp

Committer:
rmaalmeida
Date:
2017-10-03
Revision:
4:357a34c10ef2

File content as of revision 4:357a34c10ef2:

#include "kernel.h"
#include "mbed.h"
#include "lcd.h"


#define MIN_INT -30000
Ticker tick;

static process* pool[POOL_SIZE];
//primeiro elemento do buffer
int start;
//�ltimo elemento do buffer
int end;

//adiciona os processos no pool
char kernelAddProc(process* func){
	// adiciona processo somente se houver espa�o livre
	//o fim nunca pode coincidir com o inicio
	if ( ((end+1)%POOL_SIZE) != start){
		//adiciona o novo processo e agenda para executar imediatamente
		func->deadline += func->period;
		pool[end] = func;
		end = (end+1)%POOL_SIZE;
		return SUCCESS; //sucesso
	}
	return FAIL; //falha
}
//inicializa o kernel em conjunto com a controladora de drivers
void kernelInit(void){
	start = 0;
	end = 0;
	tick.attach(&kernelTick, 0.01); // setup ticker to call flip every 0.7 seconds
}
//executa os processos do 'pool' de acordo com seus tempos de execu��o
void kernelLoop(void){
	unsigned int count;
	unsigned int next;
	process* tempProc;
	for(;;){
	if (start != end){
		//Procura a pr�xima fun��o a ser executada com base no tempo
		count = (start+1)%POOL_SIZE;
		next = start;
			while(count!=end){
			if ((pool[count]->deadline) < (pool[next]->deadline)){
				next = count;
			}
			//para poder incrementar e ciclar o contador
			count = (count+1)%POOL_SIZE;
		}
		//troca e coloca o processo com menor tempo como o pr�ximo
		tempProc = pool[next];
		pool[next] = pool[start];
		pool[start] = tempProc;
		while((pool[start]->deadline) > 0){
			//lcdCommand(0xC0);
			//lcdNumber(pool[start]->deadline);
			//coloca a cpu em modo de economia de energia
		}
		//retorna se precisa repetir novamente ou n�o
		switch (pool[start]->function()) {
			case REPEAT:
				kernelAddProc(pool[start]);
				break;
			case FAIL:
				break;
			default: ;
		}
		//pr�xima fun��o
		start = (start + 1) % POOL_SIZE;
		}
	}
}
//atualiza os tempos de execu��o dos processos
void kernelTick(void){
	int proc;
	proc = start;
	while(proc!=end){
		if((pool[proc]->deadline)>(MIN_INT)){
			pool[proc]->deadline--;
		}
		
		proc = (proc+1)%POOL_SIZE;
	}

}