mBed code

The controller (www.mbed.org) is a full C++ based micro controller, with many built in features. It does not natively support PWM input however. After scouring mbed.org, and found a header PwmIn.h that did exactly what I needed, by duration (or period, or percent).

nBed with mBed, it’s as easy as pi. (a sine reference)

//Alex McAlpine 06/30/2011 www.BrainLubeOnline.com

//This is an example of the mBed acting as the shift-registers for the SNES

//5 pins connect SNES

//1 white to 5+

//7 Brown to GND

//5 (12 mbed)When Latch (Orange) is HIGH function to read 16 bit variable

//6 (11 mbed)each pulse from clock (Yellow/Red) read from 16 bit variable

//4 (13 mbed)Send data out in pulses

//Pins 21-26 are PwmIn Pins

//preprocessor directives

#include "mbed.h"

#include "PwmIn.h"

//Diagnostic declarations

DigitalOut led1(LED1);

DigitalOut led2(LED2);

DigitalOut led3(LED3);

DigitalOut led4(LED4);

//PWM In from Futaba R617FS 6 channel receiver

PwmIn UpDown_chan(p21);

PwmIn LR_chan(p22);

PwmIn XY_chan(p23);

PwmIn AB_chan(p24);

PwmIn Start_chan(p25);

PwmIn Select_chan(p26);

//Shift Register operations declarations

InterruptIn clock_in(p11);

DigitalIn latch(p12);

DigitalOut data_out(p13);

int index = 0; //index for output of register

bool bit_field_16[16] = {1,1,1,1,1,1,1,1,1,1,1,1,0,0,0,0}; //The last are for

//the super scope and other attachments they are always HIGH in the standard comntroller

//This could also be accomplished via bit manipulation with a single 16-bit short unsigned int

//More can be found on this at http://en.wikipedia.org/wiki/Bit_manipulation

//For example:

short unsigned int 16BITregister = 61440; //1111 0000 0000 0000

void get_input()

{

//if UP then bit 5 HIGH else LOW

if(UpDown_chan.pulsewidth()< .0015) {led1 = 1;bit_field_16[4] = 1;} else {led1 = 0;bit_field_16[4] = 0;}

//if DOWN then bit 6 HIGH else LOW

if(UpDown_chan.pulsewidth() > .0016) {led2 = 1;bit_field_16[5] = 1;} else {led2 = 0;bit_field_16[5] = 0;}

//if LEFT then bit 7 HIGH else LOW

if(LR_chan.pulsewidth()< .0015) {bit_field_16[6] = 1;led3 = 1;} else {bit_field_16[6] = 0;led3 = 0;}

//if RIGHT then bit 8 HIGH else LOW

if(LR_chan.pulsewidth()> .0016) {bit_field_16[7] = 1;led4 = 1;} else {bit_field_16[7] = 0;led4 = 0;}

//if 'A' then bit 9 HIGH else LOW

if(AB_chan.pulsewidth()<.0015) {bit_field_16[8] = 1;} else {bit_field_16[8] = 0;}

//if 'B' then bit 1 HIGH else LOW

if(AB_chan.pulsewidth()>.0016) {bit_field_16[0] = 1;} else {bit_field_16[0] = 0;}

//if 'X' then bit 10 HIGH else LOW

if(XY_chan.pulsewidth() <.0015) {bit_field_16[9] = 1;} else {bit_field_16[9] = 0;}

//if 'Y' then bit 2 HIGH else LOW

if(XY_chan.pulsewidth() >.0016) {bit_field_16[1] = 1;} else{bit_field_16[1] = 0;}

//if 'L' then bit 11 HIGH else LOW

// if(L) {bit_field_16[10] = 1;} //Top L and R buttons not connected at this time.

//if 'R' then bit 12 HIGH else LOW

//if(R){bit_field_16[11] = 1;}

//if 'SELECT' then bit 3 HIGH else LOW

if(Select_chan.pulsewidth()< .0015) {bit_field_16[2] = 1; led3 = 1;} else {bit_field_16[2] = 0; led3 = 0;}

//if 'START' then bit 4 HIGH else LOW

if(Start_chan.pulsewidth()< .0015) {bit_field_16[3] = 1; led4 = 1;} else {bit_field_16[3] = 0; led4 = 0;}

}

void write_input() {

data_out = bit_field_16[index];

}

int main()

{

while(1)

{

while(latch)

{

clock_in.rise(&write_input);

index++;

}

index = 0;

get_input();

} //main while

} //main

AsShiftRegister.cpp

This is the code for the mBed acting as the Shift Register

This is the code I used with the 4021 ICs.

FinalSNEScode.cpp

//Alex McAlpine 06/30/2011 www.BrainLubeOnline.com

//This is the code I used. The mBed is connected directly to the shift registers

//Pins 21-26 are PwmIn Pins

//preprocessor directives

#include "mbed.h"

#include "PwmIn.h"

//Diagnostic declarations

DigitalOut led1(LED1);

DigitalOut led2(LED2);

DigitalOut led3(LED3);

DigitalOut led4(LED4);

//PWM In from Futaba R617FS 6 channel receiver

PwmIn UpDown_chan(p21);

PwmIn LR_chan(p22);

PwmIn XY_chan(p23);

PwmIn AB_chan(p24);

PwmIn Start_chan(p25);

PwmIn Select_chan(p26);

//Shift Register operations declarations

DigitalOut UP(p11);

DigitalOut DOWN(p14);

DigitalOut LEFT(p15);

DigitalOut RIGHT(p16);

DigitalOut A(p18);

DigitalOut B(p10);

DigitalOut X(p12);

DigitalOut Y(p9);

DigitalOut START(p13);

DigitalOut SELECT(p17);

DigitalOut L(p19);

DigitalOut R(p20);

void get_input()

{

//if UP then bit 5 HIGH else LOW

if(UpDown_chan.pulsewidth()< .0015) {led1 = 1;UP = 0;} else {led1 = 0;UP = 1;}

//if DOWN then bit 6 HIGH else LOW

if(UpDown_chan.pulsewidth() > .0016) {led2 = 1;DOWN = 0;} else {led2 = 0;DOWN = 1;}

//if LEFT then bit 7 HIGH else LOW

if(LR_chan.pulsewidth()< .0015) {LEFT = 0;led3 = 1;} else {LEFT = 1;led3 = 0;}

//if RIGHT then bit 8 HIGH else LOW

if(LR_chan.pulsewidth()> .0016) {RIGHT = 0;led4 = 1;} else {RIGHT = 1;led4 = 0;}