At a rough guesschrney wrote:Alright. I tried that, but cannot detect the device with i2cdetect. Other i2c-device work well, so it's more the display. This is my setup until now:
From RPi 5v [pin 2] to: a) 4k7-resistor 1, b) 4k7-resistor 2, c) LCD's VCC
From RPi GND [pin 6] to: level shifter GND one side. From level shifter GND other side to LCD's GND.
From RPi SDA0 [pin 3] to: level shifter A1. From level shifter B1 to: a) LCD's SDA and b) 4k7-resistor 1.
From RPi SCL0 [pin 5] to: level shifter A2. From level shifter B2 to: a) LCD's SCL and b) 4k7-resistor 2.
What am I missing here?
Yes +5V to HV and LCD VCC and pullup resistorschrney wrote:thanks, will give that a try. From level shifter HV pin to the LCD's VCC then?
Now you have done that is basic electrical setup appears to be right.chrney wrote:I tried this, and all the three pins of the LCD (VCC, SDA, SCL) are ~4.5V. Nevertheless, I cannot find the device using i2cdetect (I can find other devices with this command, so there's no problem there, I'd assume).
This is my setup:
RPi 5v -> Level Shifter HV + Resistor 4k7 no. 1 + Resistor 4k7 no. 2
RPi 3v3 -> Level Shifter LV
RPi SDA -> Level Shifter A3
RPi SCL -> Level Shifter A4
Level Shifter B3 -> LCD SDA + Resistor 4k7 no. 1
Level Shifter B4 -> LCD SCL + Resistor 4k7 no. 2
RPi GND -> Level Shifter GND.
Level Shifter GND -> LCD's GND
Any ideas what's wrong here? I can't figure out what more I could try.
GPIO header pin 3 = SDAchrney wrote:So, in this case I use the two pins below 3v3, right? Pin 3 and 5, that is?
If the display has no pullup resistors on it and can recognise around 3V as a logic 1 then yes. Check the datasheet.chrney wrote:Thanks again!
Could I give it a try without the level shifter, to connect the 5v, pin 3 & 5 and GND to the LCD and run i2cdetect? Or would that blow up the board?
Just double checked this you have another fault somewhere if i2cdetect -y 1 crahses system, check your board for debris (top and bottom), check your power rail (TP1 and TP2) something else is wrong.Yes, the computer is stuck, only thing that helps is to pull the plug when checking with i2cdetect -y 1.
Looks just fine to me, unplugged and reassabled the whole case. Still the same issue .Just double checked this you have another fault somewhere if i2cdetect -y 1 crahses system, check your board for debris (top and bottom), check your power rail (TP1 and TP2) something else is wrong.
Not a single one, I have just the mini-USB connected, and an ethernet cable, run everything through Putty using a PC.Have you got a load of USB stuff connected and lots on GPIO connector?