2004 display

Questions on other types of hardware and getting it talking to the ARM CPU
Post Reply
Arnold113
Posts: 7
Joined: Wed Apr 23, 2014 5:28 am

2004 display

Post by Arnold113 »

This is my first ever to use an ARM microcomputer so if I sound less than smart its because that's what I is. I'm in the process of writing a basic program to control my band saw sawmill so I'm sure I'll be needing a lot of help. But first I need to get the supper pro interfaced. First question is, can someone help me find a user manual for the QC2004A display. Also will it work with the ARM? It is for an Arduino. Thanks for your help. Arnold



basicchip
Posts: 1039
Joined: Fri Oct 19, 2012 2:39 am
Location: Lake Tahoe, CA
Contact:

Re: 2004 display

Post by basicchip »

A quick google of that turns up lots of references. The display looks to be a 20x4 character display and uses a clone of an HD44780 driver which is pretty common interface.

And the code here should give you a good start (this was for the 2 line version)

http://www.coridiumcorp.com/forum/viewt ... =lcd#p2388

Arnold113
Posts: 7
Joined: Wed Apr 23, 2014 5:28 am

Re: 2004 display

Post by Arnold113 »

I had googled QC2004A previously but none of the entries were any help in getting info on programing instructions. I was hoping someone had this info or knew where I could go to find it.
Also I forgot to mention that this display is a serial display.
I'm really looking forward to getting started programing and using my new SuperPRO. It makes the basic stamp look like childs play.

basicchip
Posts: 1039
Joined: Fri Oct 19, 2012 2:39 am
Location: Lake Tahoe, CA
Contact:

Re: 2004 display

Post by basicchip »

What I saw when I googled the display was a number of spec sheets, all referred to the controller and many show that it is a clone or software compatible with an HD44780.

The HD44780 is a very common controller for character displays, it uses either a nibble (4 bit) or byte wide interface. It is not a serial device. The link above is to some BASIC code that talks to a similar display and should work for the QC2004A

Arnold113
Posts: 7
Joined: Wed Apr 23, 2014 5:28 am

Re: 2004 display

Post by Arnold113 »

I was doing my searching on yahoo, after I changed to google I found the info you indicated. I searched QC2004A/serial interface and found the info I was looking for. Thanks for the help. Arnold

Arnold113
Posts: 7
Joined: Wed Apr 23, 2014 5:28 am

Re: 2004 display

Post by Arnold113 »

A few problems now. First, I haven't been able to get the right code to get thru to the 2004 display yet. Being new to ARM basic and to I2C sure isn't helping. If someone could get me started in the right direction it would be great. Also, I have questions about the address of displays. How can I tell what the address is of a display and how can I change it? I'm going to be using one 20x4 and two or more one line displays displaying info all at the same time. I sure hope yall don't get tired of my questions cause I'm sure I'll have plenty of them before this project is completed. As soon as I can get the time I'll post my project. Thanks

basicchip
Posts: 1039
Joined: Fri Oct 19, 2012 2:39 am
Location: Lake Tahoe, CA
Contact:

Re: 2004 display

Post by basicchip »

The QC2004 is not an i2c device, but a nibble/byte oriented device with register/data select, read/write line, enable line and 4 or 8 bits of data.

I took a closer look and it is a clone of the Newhaven display we used in the wirelessLCD controller, so that code (above) and recently posted schematic should be a guide for you.

Arnold113
Posts: 7
Joined: Wed Apr 23, 2014 5:28 am

Re: 2004 display

Post by Arnold113 »

I guess I haven't explained my display correctly. Yes, the QC2004A isn't an I2C device, but the serial interface bd attached to it is. (YwRobot Arduino LCM 1602 IIC) This is what I'm having problems figuring out how to communicate with.

basicchip
Posts: 1039
Joined: Fri Oct 19, 2012 2:39 am
Location: Lake Tahoe, CA
Contact:

Re: 2004 display

Post by basicchip »

I haven't dug into it, but it looks to me like the device is always going to be decoded at i2c address 0x27. I see some references on the web as to how this turns a byte into the E, RS, RW, D3-D0 lines. Though not real clear if/how you can read it. Except for checking to see if it is responding you can get by without reading from an LCD.

Frankly if you are saying you are going to have 3 of these with displays, and if there is not some jumper setting to select the address (pretty common on most i2c chips), then you might be better off just connecting all the LCDs together on all lines except the E, and use 3 separate E lines for the 3 displays.

Getting this i2c-> byte will be a bit of a challenge, but once you get some subroutines working, it might not be too bad. At least you can debug the lowest level with a simple meter.

Post Reply