mbed application board

Mbed family has grown in the last months and nowadays the available platforms include different solutions furthermore the chipsets and the MCUs on this amazing hardware are not only made by NXP but there are many other important players like Freescale and ST:

https://mbed.org/platforms/

┬áMbed community is huge and healty and the “competitors” of this prototyping platform (which are many) can’t take the leadership: mbed is still the best development platform for ARM microcontrollers. To start with mbed, one of the most one practical way is using the mbed application board, well suited to test all the features of the LPC1768:

mbed_app_board_

app_board_frontapp_board_back

Schematic:

https://mbed.org/media/uploads/chris/mbed-014.1_b.pdf

Feature list:

  1. 128×32 Graphics LCD
  2. 5 way joystick
  3. 2 x Potentiometers
  4. 3.5mm Audio jack (Analog Out)
  5. Speaker, PWM Conencted
  6. 3 Axis +/1 1.5g Accelerometer
  7. 3.5mm Audio jack (Analog In)
  8. 2 x Servo motor headers
  9. RGB LED, PWM connected
  10. USB-mini-B Connector
  11. Temperature sensor
  12. Socket for for Xbee (Zigbee) or RN-XV (Wifi)
  13. RJ45 Ethernet conenctor
  14. USB-A Connector
  15. 1.3mm DC Jack input

Details:

Form factor 55mm x 86mm x 19mm (with mbed)
128×32 Graphics LCD, SPI Interface Newhaven C12332A1Z
MOSI:p5
nRESET:p6
SCK:p7
A0:p8
3 Axis +/1 1.5g Accelerometer,I2C Interface Freescale MMA7660
SCL:p27
SDA:p28
Address:0x98
Temperature sensor LM75B
SCL:p27
SDA:p28
Address:0x90
5 way Joystick ALPS SKRHADE010
Down:p12
Left:p13
Centre:p14
Up:p15
Right:p16
2 x Potentiometers Iskra PNZ10ZA, 10k
Pot 1 (left) :p19
Pot 2 (right):p20
2 x 3.5mm Audio jack (Analog In/Out) CUI Inc SJ-3523-SMT
Analog In:p17
Analog Out:p18
2 x Servo motor headers PWM1:p22
PWM2:p21
RGB LED, PWM connected Cree Inc CLV1A-FKB
Red:p23
Green:p24
Blue:p25
Speaker, PWM Connected MULTICOMP MCSMT-8030B-3717
p26
USB-B Connector Neltron, 5075ABMR-05-SM1
USB-A Connector MULTICOMP,USB-A-V
RJ45 Ethernet conenctor Pulse Jack, J00-0045NL
1.3mm DC Jack input CLIFF, FC68145S
1.3mm
6v-9v
Centre positive

Let’s start with a simple example, useful to test the temperature sensor (LM75B) and the LCD display:

mbed_app_board__TEMP_

#include "mbed.h"
#include "LM75B.h"
#include "C12832_lcd.h"

C12832_LCD lcd;
LM75B sensor(p28,p27);
Serial pc(USBTX,USBRX);

int main ()
{ //Try to open the LM75B
   if (sensor.open()) {
      printf("Device detected!\n");

      while (1) {
          lcd.cls();
          lcd.locate(0,3);
          lcd.printf("Temp = %.2f\n", (float)sensor);
          wait(1.0);
        }

    } else {
        error("Device not detected!\n");
    }
}

On the board there is a common anode RGB LED, so that “0” is on, and “1” is off; to dimm it using PWM, remember that the closer to 0.0 the brighter, the closer to 1.0 the dimmer:

mbed_app_board-2_

#include "mbed.h"

PwmOut r (p23);
PwmOut g (p24);
PwmOut b (p25);

int main()
{
 r.period(0.001);
 while(1) {
   for(float i = 0.0; i < 1.0 ; i += 0.001) {
       float p = 3 * i;
       r = 1.0 - ((p < 1.0) ? 1.0 - p : (p > 2.0) ? p - 2.0 : 0.0);
       g = 1.0 - ((p < 1.0) ? p : (p > 2.0) ? 0.0 : 2.0 - p);
       b = 1.0 - ((p < 1.0) ? 0.0 : (p > 2.0) ? 3.0 - p : p - 1.0);  
       wait (0.01);
        }
    }
}

Pwm capabilities can be tested also using the little on board speaker:

#include "mbed.h"

DigitalIn fire(p14);
PwmOut spkr(p26);

int main()
{
    while (1) {
        for (float i=2000.0; i<10000.0; i+=100) {
            spkr.period(1.0/i);
            spkr=0.5;
            wait(0.1);
        }
        spkr=0.0;
        while(!fire) {}
    }
}

The joystick can be used to drive LED1,2,3,4 light in sequence with up, down, left, right, and pushing the button lights them all:

mbed_app_board__ALL_LED

#include "mbed.h"
 
BusIn joy(p15,p12,p13,p16);
DigitalIn fire(p14);
 
BusOut leds(LED1,LED2,LED3,LED4);
 
int main()
{
    while(1) {
        if (fire) {
            leds=0xf;
        } else {
            leds=joy;
        }
        wait(0.1);
    }
}

Many other useful examples are available at https://mbed.org/cookbook/mbed-application-board

We want to thanks the mbed team for their kind support which made this review possible.

This entry was posted in MBED, microcontrollers. Bookmark the permalink.

2 Responses to mbed application board

  1. faizan says:

    I need to Pulse Jack, J00-0045NL for my project but I am not using application board I need to connect Pulse Jack, J00-0045NL to LPC1768 can u help me with the physical connection.

Leave a Reply

Your email address will not be published. Required fields are marked *