BusOut Hello World

Fork of BusOut_HelloWorld by Mbed


The BusOut interface can be used to create an artificial bus of pins out of any digital ins. The pins do not have to have sequential hardware addressing. This example program counts up from 0 to 15 or binary 0000 to 1111 . The effect of this is turning LED1-LED4 on or off according to the number going across the bus. The example code toggles LED's on / off, if a tricolor led is on the board then the led will change colors.

IntegerbinaryLED On(1) / Off(0)
00000LED4=0 LED3=0 LED2=0 LED1=0
10001LED4=0 LED3=0 LED2=0 LED1=1
20010LED4=0 LED3=0 LED2=1 LED1=0
30011LED4=0 LED3=0 LED2=1 LED1=1
40100LED4=0 LED3=1 LED2=0 LED1=0
50101LED4=0 LED3=1 LED2=0 LED1=1
60110LED4=0 LED3=1 LED2=1 LED1=0
70111LED4=0 LED3=1 LED2=1 LED1=1
81000LED4=1 LED3=0 LED2=0 LED1=0
91001LED4=1 LED3=0 LED2=0 LED1=1
101010LED4=1 LED3=0 LED2=1 LED1=0
111011LED4=1 LED3=0 LED2=1 LED1=1
121100LED4=1 LED3=1 LED2=0 LED1=0
131101LED4=1 LED3=1 LED2=0 LED1=1
141110LED4=1 LED3=1 LED2=1 LED1=0
151111LED4=1 LED3=1 LED2=1 LED1=1


When initializing a BusOut object you initialize pins in their bit order from right to left, be careful as the bit order is the reverse of the object initializing order.

// init object
BusOut thingy(pin0,pin1,...,pin15)

// use object
thingy = (val15<<15 | ... | val1 <<1 | val0 <<0) ; // where valx corresponds to the value to be put onto pinx


API summary

Import librarymbed

No documentation found.
Fri Mar 27 20:13:06 2015 +0000
Added license to main.c file.;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbedAustin 2:f979089a5ca0 1 /* mbed Example Program
mbedAustin 2:f979089a5ca0 2 * Copyright (c) 2006-2014 ARM Limited
mbedAustin 2:f979089a5ca0 3 *
mbedAustin 2:f979089a5ca0 4 * Licensed under the Apache License, Version 2.0 (the "License");
mbedAustin 2:f979089a5ca0 5 * you may not use this file except in compliance with the License.
mbedAustin 2:f979089a5ca0 6 * You may obtain a copy of the License at
mbedAustin 2:f979089a5ca0 7 *
mbedAustin 2:f979089a5ca0 8 * http://www.apache.org/licenses/LICENSE-2.0
mbedAustin 2:f979089a5ca0 9 *
mbedAustin 2:f979089a5ca0 10 * Unless required by applicable law or agreed to in writing, software
mbedAustin 2:f979089a5ca0 11 * distributed under the License is distributed on an "AS IS" BASIS,
mbedAustin 2:f979089a5ca0 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbedAustin 2:f979089a5ca0 13 * See the License for the specific language governing permissions and
mbedAustin 2:f979089a5ca0 14 * limitations under the License.
mbedAustin 2:f979089a5ca0 15 */
mbed_official 0:717993c337df 16 #include "mbed.h"
mbed_official 0:717993c337df 17
mbed_official 0:717993c337df 18 BusOut myleds(LED1, LED2, LED3, LED4);
mbed_official 0:717993c337df 19
mbed_official 0:717993c337df 20 int main() {
mbed_official 0:717993c337df 21 while(1) {
mbed_official 0:717993c337df 22 for(int i=0; i<16; i++) {
mbed_official 0:717993c337df 23 myleds = i;
mbed_official 0:717993c337df 24 wait(0.25);
mbed_official 0:717993c337df 25 }
mbed_official 0:717993c337df 26 }
mbed_official 0:717993c337df 27 }