Resolved by Rich!
Hey guys.
I'm having a little trouble with an LCD display I recently purchased. I have read through some of the posts on the forum to help me get this going, but I need a little more help. I have it connected to D12 going through a 5v regulator. Ground to ground, Vcc to Vcc, and SDA (which I believe to be RX) to a signal pin. It lights up but when I try SendSerial(d12, 9600, "Hello" ) nothing happens. I have also tried a different port and changed baud rates, no change.
Now I believe this is a serial (what I was after) and i2c compatable so it should work. I havn't found a data sheet for it yet but here's a link to it, if it helps. Any ideas what's going wrong, or even if this thing is compatable with the v4? I hope some one can help as I would love to get this working.
Thanks in advance.
I can also confirm that the LCD does work with 3.3VDC, nothing else needed besides the pullups.
Pullup resistors are used to overcome line capacitance on an I2C communication bus which can operate up to 400pF. If you look at I2C signals with an oscilloscope you can see that the clock and data signals usually look like a shark fin (capacitive effect) but when you add pullups it makes those signals "squarer" and easier to be read by the application processor. Those signals sometimes don't even reach the voltage level needed (3.3V) and thus get "pulled up" by the resistors to a 3.3V level in order to make a solid "High" signal.
The further away you get away from the application processor the stronger (lower resistance value) you'll need.
Ok, I'm kinda with you and it's making a little bit more scense to me now. Thanks for explaining it Jeremie.
Lol, sorry for the geek speak. I think that if you google some I2C signal screenshots it might make more sense
Hey, no worries. I enjoy a bit of geek speak as much as the next, er... geek.
Thanks again.
Okay. So I ordered a new display from robot electronics and it arrived this morning. I connected it up to a digital port using a 5v regulator (battery is a 7.4 LiPo), powered it up and... Nothing. It didn't light up at all. The battery is fully charged, EZ-B connected, and It is wired correctly following the tech document as pictured below.
Yellow = Signal Grey = Vcc Green = GroundIt's getting power because if I hold it to my ear, I can hear a very faint high pitch electrical hum. It tried a couple of scripts, but nothing.
Any ideas?
Steve G, its not working on I2C as you have it set on serial - remove the black jumper on the 2 pin (Mode) header then it will be set to I2C.
Here is my original thread on using these displays.
synthiam.com/Community/Questions/3295
Hope this helps.
Tony
@Tony... I think Steve is actually trying to use serial, not I2C....
Richard R, I missed that, I saw Jeremie was talking about I2C on the previous page so I thought is was I2C. With I2C Steve G would have needed 4 connections (SDA,SCL,+5,GND) to make it work, so I guess that should have given me a clue!