Surplus brand new OEM 20x4 Serial LCDs for sale (also Prop versions too)
Peter Jakacki
Posts: 10,193
I've mentioned in another thread that I have a few boxes of 20x4 serial LCDs surplus from supplying an OEM for many years. The displays are high quality (expensive) Winstar high-contrast FSTN amber backlit LCDs with my own surface mount backpack, so the whole display depth is less than 15mm from the front of the bezel. It is actually lower than the bezel's metal tab height on the rear but the low profile pushbutton that adjusts the contrast digitally just pokes 1mm above this. Here is a link to the datasheet which I will also attach and the command set is as compatible with standard ASCII devices as possible with extra commands for changing the contrast and dimming the backlight etc.
Currently the firmware supports big 4 digit mode over 4 lines but I may update these to allow 6 digit mode over 3 lines. Each display includes a small piezo buzzer and originally these were mounted on the rear since depth didn't matter but I will include them separately so the user can solder them on directly or via a lead. There are no DIP switches, one, because I detest bulky switches (and trimpots too), and two, because we can do it much better storing configurations in EEPROM. By default the displays are 9600 baud but can be set up to 115200 baud and polarity is programmable but I will default them to logic level although they can take full voltage RS-232. A single 5-pin right-angle pin header will be supplied (normally 10-pin vertical) so that it is easy to plug in a 3 or 4 pin header although a 5-pin plug would be reversible (VCC,GND,RXD,GND,VCC). BTW, these LCD modules do require 5V and with the initial dimmed backlight it consumes 70ma but you can turn the backlight on and off or even adjust the brightness up or down.
Here is a shot of the backpack (older version) on the LCD minus a connector and piezo.
EDIT - found a newer backpack (a reject)
The trouble is though that I'm not setup to handle little orders mainly because the shipping costs are ridiculous for small items and it is fiddly I find unless I setup shop to do it properly. What I will do though for forum members is offer a box of 10 serial LCDs for $180 USD including shipping 6 day economy air, that's less than $18 each and what I believe is the best of all the serial displays out there. I was doing serial LCDs long before well known brands started doing them. I haven't checked to see how many I have in stock but it is definitely over 100, maybe 150 units. Each display is individually boxed so they can be easily individually reshipped if anyone wants to recoup some costs.
ALSO
I also have a box load of P1144 MultiLCD modules which use the same Winstar LCD but have a pcb backpack the same size as the display with the Propeller, a much larger and louder 30mm piezo transducer (for melodies), a full size SD card with access from the bottom, connector for keypad scanning up to 8x4, a 3.5mm audio socket for audio out, and a USB socket that is designed to take PS/2 enabled USB keypads. Also includes RS485 and provision for a SMPS module so that it can be powered from any DC source up to 50V. Sure, you can drive these serially or run them standalone which I also did for some custom song boxes where you punch a song/track number and it would play the wave files. Using Tachyon you can communicate with a network of these over many hundreds of meters and deploy new firmware etc. I don't have a datasheet for this one yet but I have used quite a few of these in various projects so I will post more information about these later. I will do a similar plus cost deal on these for a box of 10 for $250 USD inc shipping.
Currently the firmware supports big 4 digit mode over 4 lines but I may update these to allow 6 digit mode over 3 lines. Each display includes a small piezo buzzer and originally these were mounted on the rear since depth didn't matter but I will include them separately so the user can solder them on directly or via a lead. There are no DIP switches, one, because I detest bulky switches (and trimpots too), and two, because we can do it much better storing configurations in EEPROM. By default the displays are 9600 baud but can be set up to 115200 baud and polarity is programmable but I will default them to logic level although they can take full voltage RS-232. A single 5-pin right-angle pin header will be supplied (normally 10-pin vertical) so that it is easy to plug in a 3 or 4 pin header although a 5-pin plug would be reversible (VCC,GND,RXD,GND,VCC). BTW, these LCD modules do require 5V and with the initial dimmed backlight it consumes 70ma but you can turn the backlight on and off or even adjust the brightness up or down.
Here is a shot of the backpack (older version) on the LCD minus a connector and piezo.
EDIT - found a newer backpack (a reject)
The trouble is though that I'm not setup to handle little orders mainly because the shipping costs are ridiculous for small items and it is fiddly I find unless I setup shop to do it properly. What I will do though for forum members is offer a box of 10 serial LCDs for $180 USD including shipping 6 day economy air, that's less than $18 each and what I believe is the best of all the serial displays out there. I was doing serial LCDs long before well known brands started doing them. I haven't checked to see how many I have in stock but it is definitely over 100, maybe 150 units. Each display is individually boxed so they can be easily individually reshipped if anyone wants to recoup some costs.
ALSO
I also have a box load of P1144 MultiLCD modules which use the same Winstar LCD but have a pcb backpack the same size as the display with the Propeller, a much larger and louder 30mm piezo transducer (for melodies), a full size SD card with access from the bottom, connector for keypad scanning up to 8x4, a 3.5mm audio socket for audio out, and a USB socket that is designed to take PS/2 enabled USB keypads. Also includes RS485 and provision for a SMPS module so that it can be powered from any DC source up to 50V. Sure, you can drive these serially or run them standalone which I also did for some custom song boxes where you punch a song/track number and it would play the wave files. Using Tachyon you can communicate with a network of these over many hundreds of meters and deploy new firmware etc. I don't have a datasheet for this one yet but I have used quite a few of these in various projects so I will post more information about these later. I will do a similar plus cost deal on these for a box of 10 for $250 USD inc shipping.
800 x 346 - 102K
Comments
While this is beyond the normal limit of my "hobby allowance" to myself, I'm willing to purchase of 10 of each if I can get a reasonable sense that I can unload the balance to interested parties in California / Los Angeles.
Shall I cross-post this flimsy offer on the original thread?
I'm interested in your second product, the P1144 MultiLCD. Can you post info on that? Google is no help.
Please post more information on the Propeller based P1144 product as it would solidify it as a bonafide entry to this category.
Not sure why you want to limit sales to a certain area. I handled Peter's P2D2 distribution to US and Canada. US post is pretty much the same to both coasts.
I'm in for two of each if you want to pursue it.
Publison and I chatted outside the thread and are considering options... Stay tuned...
Thanks for that update, Peter. Really nice module! Those should sell.
I'll take the remaining Prop LCD from a box of 10 - Publison wants 2, I'll take the remaining 8, If anyone else wants a few, take them from my 8. I'm flexible on these numbers for this module.
Does this make sense? Not sure how many octetta needs.....
I'm on Kauai which is still in the US - flat rate shipping is offered via USPS.
Open to any ideas. I'm willing to be the distribution point even though I'm in the middle of the Pacific.
I will check the limited stock on these but I can make up a few more if needed so that nobody misses out, and if need be ship them individually. Just to be on the safe side I will probably need to drop by the post office with a packaged unit to check what it will cost though and I will let you know. But there are a couple of members in the US that are interested in buying a box of 10 and reselling the extras and I think that might be a better option.
It's Monday now and I will get back shortly to anybody that has already enquired.
David, There will be shipping involve with these. I can't eat the shipping like I did with the P2D2 boards. We are pretty close, so it should be minimal. On orders of multiple displays, I'll do Priority shipping.
Maybe I might turn the backlight off by default. These are the figures for various settings:
0 =6ma
1 = 18ma
2 = 33ma
3 = 47ma
4 = 60ma
8 = 130ma (half)
12 = 169ma
14 = 197ma
16 = 260ma (full)
These LCDs are really low-profile so you will be able to squeeze them into some tight spaces, even though they are backlit. I will include a small piezo-buzzer separately that you can choose to solder on if you want.
Thanks Peter! Thanks Publison!
READ THE MANUAL (and don't believe it)
On another note but in similar vein in that I have never seen it touched upon is the character LCD instruction timing. Everywhere I look I see that the $01 CLEAR DISPLAY instruction takes around 1.6ms as does the $02 RETURN HOME but all other instructions take <40us including the functionally equivalent home instruction $80 that sets the cursor to position 0 or home. But $02 RETURN HOME is always quoted as taking as long as CLEAR DISPLAY in all the LCD manufacturers datasheets which are all based upon the original Hitachi HD44780 controller. I happen to have a hardcopy of an Hitachi LCD controller databook from 1988 so I went back to page 129 and there it is too, exactly the same that every other clone manufacturer quotes from.
But this is wrong and I know it. So I connected up one of the Prop based LCDs I have and although I interface to a 5V display as write-only, not only for voltage compatibility since they also use TTL logic levels, but also because there is never any need to read the display simply just for the busy flag since the execution times are well known and "established". If we reason now that if the display is actually busy then it would miss data sent to it while busy, correct?
First off I test the return home command by writing directly to the LCD data bus with my LCDCMD and LCDDAT words, the only difference being the register select line for command or data. First I clear the display separately since it is not part of the test with 1 LCDCMD and then I send a RETURN HOME command followed by 80 data characters so timed that they take about 50us each so as to give a timing margin on top of the 40us figure.
Here is the code: If I'm right then I should see the 20x4 display full of A's which I do and none missing.
But executing the same line using 1 LCDCMD instead shows many missing since it was busy and in fact I count 49 A's which means it dropped 31 characters times 50us which is around 1.55ms as it should be.
What does this tell you? You should not only always Read The Manual, but you should always check for yourself when it doesn't seem to make sense. All these years though I have indeed been working under the correct assumption because I am sure I tested this out a long time ago. Always look in the box to make sure it is so, don't trust the label and likewise with datasheets and manuals.
I worked in a software store long ago (when there were software stores) we sold mainly games for the IBM.
Every day people would call in to say that they couldn't install their game.
We would always ask "Did you read the instructions ?" they would say "yes" and we would reply "That was your first mistake".
We were not trying to be funny...More times than not, the install instructions were wrong.
People would always laugh, and then we would walk them thru DIR and look for INSTALL.EXE or SETUP.EXE or whatever it was.
So, yeah. Don't believe everything on a datasheet.
Bean
That's true about "instruction manuals", I don't use them myself and if you did have a problem they don't give you a clue either so I laugh when I see someone trying to read the instruction manual before they even begin! Of course I tell them to throw the "manual" into the bin and just give it a go.
However, for designers you'd expect datasheets with detailed electrical, mechanical, environmental, and programming information to be correct. But I've always laughed at the absurdity of a slow 8-bit data bus (with a high enable signal) just to run an LCD which might have made sense in the 70's maybe but by the 80's many faster single chip controllers were becoming available and so these displays were being driven from I/O ports instead of data buses. What a waste of I/O when some kind of serial would have been sufficient. But down through the decades Hitachi and all the cloners still make them with this slow data bus which is why serial backpacks are the go.
Sheeesh!
"Incorrect documentation is often worse than no documentation." — Bertrand Meyer
Jim
These are packed and ready to send tomorrow so they will take about 6 days.
I totally updated the firmware for these just to make it really flexible. Baud rates work from 300 to 125k, TTL or RS232 polarity, 16 backlight levels, digital contrast, forced defaults, on-screen reporting etc. Lots of testing to make sure they are ok. I'm updating the datasheet as well. The serial input is designed for full RS232 levels but works down to 2V levels too but there is no concern about having a signal present when they are not powered up. I went through the stock and found I had well over 200 left!
Still have 34 left.
Jim
No, Jim. Peter has been very busy with P2 and TAQOZ testing. I imagine he will get them out shortly. I'm looking forward to them too!
We'll let you know when we need lcd modules. Just finishing some personal projects on the truck, waiting for led light bars, cover and railings kit.