Anyone used a 24x2 LCD?

[nbw]

I'm thinking of putting one on my amplifier I'm making. It's a HD44--- usual type, and I have a picaxe serial LCD chip spare.

Just wondering about the character positions though.

On the 16x2s I've used, row 1 is 128 + 15 characters, the second row starts at192 + 15.

Has anyone used a 24x2, and is it simply 128 + 23 characters, and 192 + 23?

kind regards
El Barno

 

[premelec]

With PHA555 LCD118

I've used some 24 x 2 units salvaged from Rolm telephone units - using Peter Anderson's LCD118 driver chip... seems to work fine... however I don't know how much of the intelligence is in the LCD118 and how much in the 24 x 2 unit!

I forgot to mention that my LCD units have non-logical ribbon cable sequence - the color marked wire on the flat cable is #2 instead of #1 - etc... so check to make sure your cable is correct to the LCD circuit board... probably just a production error on my particular unit!

 

[westaust55]

@nbw,

do you have the datasheet (or a link) for the 24x2 LCD you have.

Based on many LCDs, as an educated guess I think you will have

Row 1 : 128 to 128+23
Row 2 : 192 to 192+23


In terms of the controllers, even a 20x4 is really just a 40x2 with the two rows "folded" as
first half row 1
first half row 2
second half row 1
second half row 2

 

[nbw]

The one I have in mind (now ordered) is a red 24x2 LCD from sure electronics. The prices there are excellent, but they cane you on the shipping.

A 24 char display will nicely allow me to display the amplifier temp and watts usage, as well as the volts and current moving through the toroidal transformer. Plus, the speed at which the fan is being PWmed by the 18x, should the heatsink need a little extra cooling.

The case is electroplated copper and the VU display is retro red LED, so I wanted to keep a similar colour theme going with the red display.

Price was US3.42, and US6 to ship it!

 

[hippy]

Most LCD's have a 128 byte RAM ( $80-$FF for the sake of argument ) which is then mapped to the actual display. Usually line 1 starts from $80 (128), line 2 from $C0 (192) no matter what the display size; 1x16 is the odd one as that's two concatenated 1x8 lines. The second line may for some controllers be somewhere else but easy enough to find by writing to various RAM addresses.

What the Shift and Scroll commands do for an LCD is move the display window over the RAM, so you can fill RAM with long lines of text then simply Shift the display to start from say second character of that text.

 

[nbw]

thanks for that Hippy. I was fairly hopeful that a bog standard chip controller and a pain-relieving serial LCD IC would be able to write to it. Hopefully it should arrive soon and I'll be able to throw some addresses at it.

I also have a 2x8 I'll have a play with as well.

A shame about sure electronics shipping... their stuff is so cheap, but the postage more than doubles it. You can get some LCDs for ~USD2 ! Takes the cost from 'dirt-cheap' up to 'reasonable'.

 

[westaust55]

thanks for that Hippy. I was fairly hopeful that a bog standard chip controller and a pain-relieving serial LCD IC would be able to write to it.

Are you thinking to use the Rev Ed FRM010 chip ?
or something like a PH Anderson (or similar) serial interface board?

 

[nbw]

Yes indeed, I have one of those FRMs kicking around so I thought this would be a good use. Although I've bit-mangled a 16x2 before and I'll have about 1000 bytes spare in the 18x, I just thought an FRM could allow me to move my head-banging to another part of the project, such as making my copper bars to connect my 20,000uF worth of caps to the supply rails