hi

where do you live, could it be an idea to send display bread board and netduino to you for testing ?

(incl power power supply ?)

ok thanks. I will wait for your testing

when i only connect the powersupply and nothing else the voltage on the 5V DC is 4.81 VDC ?

on both my Netduino's ? So what could be wrong then ?

1. 8.70 VDC

2. 4.67 VDC

3. 4.67 VDC

4. 4.65 VDC

5. 0 VDC

when i disconnect the SDA from the netduino i have 4,58 VDC with connection to the netduino it is 0VDC.

i'm getting crazy it was 4,58 VDC before when it was connected.

not really

i sold a more powerfull powersupply (1500 mA).  I thought that would help.

The voltage on the SD line is 4,62 VDC now. But it does not seem to help.

If i have a seperate powersupply for the display is it only for the display itself or also for the i2c logic ?

i can look if have any which i can cut the wires.

hi studied electronics so i should know what i am doing !!

it is a long time ago i did something with it.

See attachments for pics.

Red is +5V

Green is gnd

Vin 8,72

5V on netduino 4.69

SD 4.64 VDC

SC 4.63 VDC

you mean the left red wire.on the connector with 3 pins ?

i bought a new netduino and a new display but still the same.

can somebody help me ?

Some one in the Netherlands or Belgium or Germany which can help me local

hi did you find any time :-)

what would be the next step, buy a new one ?

ok i did that then the measurement are as in the previous post

with the external power supply of 9VDC 500ma i get a voltage of 4,58VDC on the SDA line and also on the SCLLine.

but it does not get any tekst so i2c is still not working.

What could be the problem is the voltage still to low ? (many thanks for your help until now).

great i can just connect usb for debugging ?

and the external power supply where do i connect that just to the +5v and gnd of the netduino ?

Hi it is a dutch site

https://www.iprototy...cts/components/led-lcd/lcd16x2-I2C-BL

there is a library for arduino on that site.

oke thanks, i will order one of those displays. But do you have the source code for me for these displays ?

Which resistors should i use and which voltage for these?

It is a LiquidCrystal_I2C

Can you also help me with the resistors and the connections

thanks all for your answers.

i think i have to start from the beginning.

How do i connect the bus ? Which resistors do i need ? and can give someone me some example code to test if a can connect / communicatie with a slave ?

       OutputPort op = new OutputPort(Pins.GPIO_PIN_SDA, true);
            bool noton=false;

            while (true)
            {
                noton=!noton;
                op.Write(noton);
                Thread.Sleep(200);
            }

Hi Chris

i have a netduino 2 plus connected to SDA/SCL and one netduino 2 connected to A4/A5

The resistors are 4k7.

I another thread you where talking about testing with a led. I tried that also but maybe i did something but the led never turns on.

Pin 4 -> resistor 150 Ohm -> led -> gnd  , i already turned the led from positive to negative but no result.

this is the code

finally found someone to solder for me.

Now i connected the power supply from the netduino but the lcd does not turn on ?

Is the power of the netduinoe not enough for the lcd ?

oke the square does nog seem to be pin 1. but the oppesite pin seams to be pin 1.

When i connect the power supply the lcd lights up.

i connected SDA and SCL to the SDA en SCL connectors on the netduino 2.

The code is running but i do net get hello on the lcd ? Wat can i test to get it up and running ?

oke i will try tomorrow.

only the lcd part. The i2c part will be supplied from the netduino ?

that is 5v? when i measure 4,23 Volt.

When measuring without any connection to the netduino the voltage is 4.68 volt.

to be sure

i have a netduino plus 2 i connected sda/scl to the sd/sc connector

that is correct ?

i also have a netduino 2 there i connect to Analog 4 and 5?

that is correct ?

1. Yes there  is.

2. The voltage is 4.23V is that high enough ?

3. Delay does not help.  When debugging i can make a delay also

4. the return value is zero, also when i disconnect the i2c bus ?

5. I tried it is returning zero but the brightness does nog change

any other things i can do ?

Hi

i have a LCD display with I2C.

I tried for a few days now, but total no communication.

Is there a piece of sample code to test I2c ?  Maybe ask the device adresses on the bus or something

thanks Frank