mbed API for Raspberry Pi boards.

mbedPi

This is an attempt to implement a limited number of mbed APIs for Raspberry Pi single-board computers. The project was inspired by and based on the arduPi library developed for the Arduino by Cooking Hacks .

/media/uploads/hudakz/board01.jpg

Specifications

  • Chip: Broadcom BCM2836 SoC
  • Core architecture: Quad-core ARM Cortex-A7
  • CPU frequency: 900 MHz
  • GPU: Dual Core VideoCore IV® Multimedia Co-Processor
  • Memory: 1GB LPDDR2
  • Operating System: Boots from Micro SD card, running a version of the Linux operating system
  • Power: Micro USB socket 5V, 2A

Connectors

  • Ethernet: 10/100 BaseT Ethernet socket
  • Video Output: HDMI (rev 1.3 & 1.4)
  • Audio Output: 3.5mm jack, HDMI
  • USB: 4 x USB 2.0 Connector
  • GPIO Connector: 40-pin 2.54 mm (100 mil) expansion header: 2x20 strip providing 27 GPIO pins as well as +3.3 V, +5 V and GND supply lines
  • Camera Connector: 15-pin MIPI Camera Serial Interface (CSI-2)
  • JTAG: Not populated
  • Display Connector: Display Serial Interface (DSI) 15 way flat flex cable connector with two data lanes and a clock lane
  • Memory Card Slot: Micro SDIO

GPIO connector pinout

Zoom in /media/uploads/hudakz/mbedpi_pinout02.png

Information

Only the labels printed in blue/white or green/white (i.e. p3, gpio2 ...) must be used in your code. The other labels are given as information (alternate-functions, power pins, ...).


Building programs for the Raspberry Pi with mbedPi

I use Qt Creator for development, however you can use any other IDE available on the Raspberry Pi (e.g. Geany) if you like. For a quick try:

  • Install Qt and the Qt Creator onto your Raspberry Pi. Then create a new "Blinky" Plain non-Qt C++ Project as follows: /media/uploads/hudakz/newproject.png

  • Change the main code as below:

main.cpp

#include "mbedPi.h"

int main()
{
    DigitalOut  myled(p7);

    while(1) {
        myled = 1; // LED is ON
        wait(0.2); // 200 ms
        myled = 0; // LED is OFF
        wait(1.0); // 1 sec
        printf("Blink\r\n");
    }
}


  • Copy the mbedPi.zip file into your project's folder and unzip.
  • Add the mbedPi.h and mbedPi.cpp files to your project by right clicking on the "Blinky" project and then clicking on the "Add Existing Files..." option in the local menu:

    /media/uploads/hudakz/addfiles.png

    /media/uploads/hudakz/addfiles02.png

  • Double click on Blinky.pro to open it for editing and add new libraries by inserting a new line as follows:

    /media/uploads/hudakz/libs.png

  • Compile the project.

  • Connect an LED through a 1k resistor to pin 7 and the ground on the Raspberry Pi GPIO connector.

  • Run the binary as sudo (sudo ./Blinky) and you should see the LED blinking. /media/uploads/hudakz/mbedpi_run.png

  • Press Ctrl+c to stop running the application.
Committer:
hudakz
Date:
Tue Dec 20 12:16:18 2022 +0000
Revision:
2:131555dc6fb7
Parent:
rpi_wizard/qbs_rpi/js/helpers.js@1:1f2d9982fa8c
Mbed API for Raspberry Pi boards equipped with BCM2836 SoC.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
hudakz 1:1f2d9982fa8c 1 var Process = require("qbs.Process");
hudakz 1:1f2d9982fa8c 2 var File = require("qbs.File");
hudakz 1:1f2d9982fa8c 3
hudakz 1:1f2d9982fa8c 4 function findCommand(){
hudakz 1:1f2d9982fa8c 5 // check if it's unix
hudakz 1:1f2d9982fa8c 6 if(File.exists("/usr/bin/find")){
hudakz 1:1f2d9982fa8c 7 return "/usr/bin/find";
hudakz 1:1f2d9982fa8c 8 }
hudakz 1:1f2d9982fa8c 9
hudakz 1:1f2d9982fa8c 10 // else msys2, search unix find command
hudakz 1:1f2d9982fa8c 11 var where = new Process();
hudakz 1:1f2d9982fa8c 12 where.exec("where.exe", ['find'], true);
hudakz 1:1f2d9982fa8c 13 if(where.exitCode()!==0){
hudakz 1:1f2d9982fa8c 14 throw("error: There is a problem to detect the 'find' command."+where.exitCode());
hudakz 1:1f2d9982fa8c 15 }
hudakz 1:1f2d9982fa8c 16
hudakz 1:1f2d9982fa8c 17 while(true){
hudakz 1:1f2d9982fa8c 18 var line = where.readLine();
hudakz 1:1f2d9982fa8c 19 if(line!=="" && line!==undefined){
hudakz 1:1f2d9982fa8c 20 var findPos = line.indexOf("bin\\find.exe");
hudakz 1:1f2d9982fa8c 21 if (findPos > -1){
hudakz 1:1f2d9982fa8c 22 return line;
hudakz 1:1f2d9982fa8c 23 }
hudakz 1:1f2d9982fa8c 24 }else{
hudakz 1:1f2d9982fa8c 25 break;
hudakz 1:1f2d9982fa8c 26 }
hudakz 1:1f2d9982fa8c 27 }
hudakz 1:1f2d9982fa8c 28 where.close()
hudakz 1:1f2d9982fa8c 29 return "find";
hudakz 1:1f2d9982fa8c 30 }
hudakz 1:1f2d9982fa8c 31
hudakz 1:1f2d9982fa8c 32 function dirs(dir){
hudakz 1:1f2d9982fa8c 33 var ret = []
hudakz 1:1f2d9982fa8c 34 if(!File.exists(dir)){
hudakz 1:1f2d9982fa8c 35 return ret;
hudakz 1:1f2d9982fa8c 36 }
hudakz 1:1f2d9982fa8c 37 var find = new Process();
hudakz 1:1f2d9982fa8c 38 var params = [dir,'-type','d'];
hudakz 1:1f2d9982fa8c 39 find.exec(findCommand(), params)
hudakz 1:1f2d9982fa8c 40 if(find.exitCode()!==0){
hudakz 1:1f2d9982fa8c 41 var error = find.readStdErr();
hudakz 1:1f2d9982fa8c 42 throw("error: " + error)
hudakz 1:1f2d9982fa8c 43 }
hudakz 1:1f2d9982fa8c 44 var line = find.readLine();
hudakz 1:1f2d9982fa8c 45 while(line.trim()!==""){
hudakz 1:1f2d9982fa8c 46 ret = ret.concat([line.trim()]);
hudakz 1:1f2d9982fa8c 47 line = find.readLine();
hudakz 1:1f2d9982fa8c 48 }
hudakz 1:1f2d9982fa8c 49 find.close();
hudakz 1:1f2d9982fa8c 50 return(ret)
hudakz 1:1f2d9982fa8c 51 }
hudakz 1:1f2d9982fa8c 52
hudakz 1:1f2d9982fa8c 53 function getTimes() {
hudakz 1:1f2d9982fa8c 54 var d = new Date()
hudakz 1:1f2d9982fa8c 55 var current = d.getTime()/1000 // To seconds
hudakz 1:1f2d9982fa8c 56 var timezone = d.getTimezoneOffset()*60 // To seconds
hudakz 1:1f2d9982fa8c 57 var daylight = 0
hudakz 1:1f2d9982fa8c 58
hudakz 1:1f2d9982fa8c 59 return {"utc":current.toFixed(),
hudakz 1:1f2d9982fa8c 60 "local":(current+timezone+daylight).toFixed(),
hudakz 1:1f2d9982fa8c 61 "zone":timezone.toFixed(),
hudakz 1:1f2d9982fa8c 62 "dst":daylight.toFixed()}
hudakz 1:1f2d9982fa8c 63 }
hudakz 1:1f2d9982fa8c 64
hudakz 1:1f2d9982fa8c 65