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Forum Index : Microcontroller and PC projects : Question about LCD controllers....
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9590 |
The manual for the uM page 19, talks about using LCD modules. I would like to use 20x4 LCD module, but am unsure of controller compatiblility. It says it uses the 6A0069 controller, which looking at the manual, mentiones KS0066, which is close, but not exact. The LCD can be found here. Is it false-logic to assume that all parallel LCD's will accept the same common instruction set for basic use? (ignore special features like RAM or custom character generation etc - only need 0-9 and A-Z) EDIT: Here is the link to the S6A0066 controller used in these LCD's. I am reading it now, to see if it enlightens me.... Smoke makes things work. When the smoke gets out, it stops! |
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| WhiteWizzard Guru  Joined: 05/04/2013 Location: United KingdomPosts: 2932 |
I haven't checked out the one you mention but I thought I would let you know about this one. It is a 4x20 yellow OLED (so really, really nice and clear to read from any angle). It is also HDD44780 compatible so works with all the MMBasic's LCD commands. Total draw is around 40mA (but cost is higher relative to the many cheap LCDs out there). The link is to my local high-street supplier (prices there are double what you should pay) but I am sure cheap OLEDs are available on eBay as a cheaper alternative. Sorry it doesn't answer your question - just letting you know my preference to LCDs (after all, I manage to get you 'converted' to FRAMs  )
WW |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9590 |
Excellent point, my man. I will investigate. Don't really care THAT much about price difference, if it is a better display. The LCD backlight is the most greedy part of the whole thing!  Smoke makes things work. When the smoke gets out, it stops! |
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OA47 Guru Joined: 11/04/2012 Location: AustraliaPosts: 982 |
Grogster, I purchased some cheap 20X4 displays from ebay that I have used in some projects. I couldn't get my purchase history to go back far enough to post the listing but I did post a picture some time back. TBS link The only labelling on the units is J204A on the PCB. Hope this info may help. GM |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9590 |
I guess I might just try it. At worst, it won't work, and I will have a spare LCD for other things! I will let you all know what happens. Smoke makes things work. When the smoke gets out, it stops! |
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Lou Senior Member  Joined: 01/02/2014 Location: United StatesPosts: 229 |
Grogs, Months ago I tried a 4x16 LCD from Futurlec. The first line wrote to the LCD OK but the following lines were offset by a couple characters. Someone on the Shed said it was an internal addressing difference (problem). Others had 4 line LCD's that worked OK, so all 4 line LCD's are not the equal. Lou Microcontrollers - the other white meat |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9590 |
Acknowledged. I will try it and see. I have some of those serial interface chips I could use, but I liked the idea of using the direct connection to the uM.  Smoke makes things work. When the smoke gets out, it stops! |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Graeme, I have some info on the J204A displays. They're from Systronix and use the Samsung KS0066 LCD controller - it's a clone of the Hitachi HD44780. I bought mine a couple of years ago from DX.com Greg |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9590 |
That's encouraging - my Topway LCD should work, then - with any luck.... I will let the thread know - I am expecting the LCD to be here tomorrow. Smoke makes things work. When the smoke gets out, it stops! |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9590 |
Sad to have to report, that my chosen LCD does not respond at all to the LCD commands. [code] DISPLAY: LCD Init 24,25,26,27,30,31 LCD 1,1,"Hello world!" End [/code] Running this code results in no display output at all. Twidling the contrast control also does nothing. All I ever get, is rows 1 and 3 full of black blocks. 
Oh well - was worth a try. EDIT: I think I found the LCD that Graeme was referring to, and as that seemed to work OK, I will get a couple of these. The listing does state that they use the HS0066 controller or equivalent, and are labeled J204A on the PCB as per the image and Graeme's note, so I think these ones will work. Smoke makes things work. When the smoke gets out, it stops! |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
I didn't mention that I've got a couple of those in use too Groggs so you should be OK with them. I've lost the link for the info I have so I've included the first section of it below. The tables (pinouts, font maps etc.) given on most of those sales links are in this document too and the rest of it is several pages of the HD44780U command structure - so presumably is it compatible with them. Greg Systronix 20x4 LCD Brief Technical Data July 31, 2000 Here is brief data for the Systronix 20x4 character LCD. It is a DataVision part and uses the Samsung KS0066 LCD controller. It's a clone of the Hitachi HD44780. We're not aware of any incompatabilities between the two - at least we have never seen any in all the code and custom applications we have done. This 20x4 LCD is electrically and mechanically interchangeable with 20x4 LCDs from several other vendors. The only differences we've seen among different 20x4 LCDs are: 1) LED backlight brightness, voltage and current vary widely, as does the quality of the display 2) There is a resistor “Rf” which sets the speed of the LCD interface by controlling the internal oscillator frequency. Several displays we have evaluated have a low resistor value. This makes the display too slow. Looking at the Hitachi data sheet page 56, it appears that perhaps the “incorrect” resistor is really intended for 3V use of the displays. At 5V the resistor Rf should be 91 Kohms. At 3V it should be 75 Kohms. Using a 3V display at 5V is acceptable from a voltage standpoint (the display can operate on 3-5V) but the oscillator will then be running too slowly. One fix is to always check the busy flag and not use a fixed time delay in your code, then it will work regardless of the LCD speed. The other option is to always allow enough delay for the slower display. All Systronix 20x4 LCDs have the 91 Kohm resistor and are intended for 5V operation. Thank you for purchasing Systronix embedded control products and accessories. If you have any other questions please email to support@systronix.com or phone +1-801-534-1017, fax +1-801- 534-1019. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9590 |
Thanks for that great information.  Smoke makes things work. When the smoke gets out, it stops! |
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