Differences

This shows you the differences between two versions of the page.

--- electronic:lcd:start [2018/12/17 18:49] – tony
+++ electronic:lcd:start [2026/09/26 21:02] (current) – tony
@@ Line 14: / Line 14: @@
 One of the main difficulties with re-using them is simply having the right type of connector - many old (eg 1980's)  devices had relatively large connectors with 0.1" pin spacing which was easy to solder a header to, modern devices often have tiny pin spacing and obscure/unobtainable connectors that are difficult to connect to.  So it is worth extracting connecting cables and connectors at the same time as the LCD modules when recovering them from scrapped devices.
-The second problem is working out the pin assignments of the connectors.  Again it saves a lot of time if you examine the scrapped device as you extract the LCD module,  and determine which are the power supply lines, and their voltage.  If driver chips are identifiable then you can sometimes trace their pins to the edge connector to find some of the pin assignments, but often modern modules have epoxy covering the chip or the have the chip mounted directly on LCD substrate.
+The second problem is working out the pin assignments of the connectors.  Again it saves a lot of time if you examine the scrapped device as you extract the LCD module,  and determine which are the power supply lines, and their voltage.  If driver chips are identifiable then you can sometimes trace their pins to the edge connector to find some of the pin assignments, but often modern modules have epoxy covering the chip or the have the chip mounted directly on the LCD substrate.
-Older devices are usually just straight text (often with choices of character set), and maybe dot addressable pixels or user definable characters.   Often there will be a a back-light element, either fluorescent or LED.   As technology improved the trend was towards customised display elements (eg icons, and logos) as well as text, which might limit their general re-usability.   Recent devices tend to have full colour pixel addressable displays giving maximum flexibility, but increasing driving complexity.
+Older devices are usually just straight alpha/numeric (often with choices of character set), and maybe dot addressable pixels or user definable characters.   Often there will be a back-light element, either fluorescent or LED.   As technology improved the trend was towards customised display elements (eg icons, and logos) as well as text, which might limit their general re-usability.   Recent devices tend to have full colour pixel addressable displays giving maximum flexibility, but increasing driving complexity.
 ===== Recovered LCD modules =====
 On the [[:electronic:lcd:sidebar|sidebar]] there is a list of LCD modules that I have recovered from various pieces of scrap equipment and the linked pages include pinouts and whether there is an Arduino driver for them.
-====== LCD types ======
+===== LCD types =====
 **TN** (Twisted Nematic)
@@ Line 42: / Line 42: @@
 **Transflective** LCDs have both reflecting and transmitting properties and can be viewed in direct sunlight and with a backlight for low light environments.
-====== Common LCD module pinouts ======
+===== Common LCD module pinouts =====
 ^1|Gnd|Gnd|Gnd|Gnd|Gnd|
 ^2|Vdd|Vdd|Vdd|Vdd|Vdd|
 ^3|V0|V0|V0|V0|RS|
-^4|RS|Reset|RS|RS|R/~W|
+^4|RS|Reset|RS|RS|R/W|
-^5|R/~W|RS|R/~W|R/~W|E|
+^5|R/W|RS|R/W|R/W|E|
-^6|~E|R/~W|~E|~E|DB0|
+^6|/E|R/W|/E|/E|DB0|
 ^7|DB0|E|DB0|DB0|DB1|
 ^8|DB1|DB0|DB1|DB1|DB2|
@@ Line 62: / Line 62: @@
 Key:\\
-**Gnd** : Ground, **Vdd** : +3.3V or +5V, **VO** : Contrast, **RS** :  Instruction/Data, **R/~W** :  Read/Write, **E** :  Device select, **DB0**–**7** : Data bus, **A** : Backlight +ve, **K** :  Backlight ground
+**Gnd** : Ground, **Vdd** : +3.3V or +5V, **VO** : Contrast, **RS** :  Instruction/Data, **R/W** :  Read/Write, **E** :  Device select, **DB0**–**7** : Data bus, **A** : Backlight +ve, **K** :  Backlight ground
+\\
 Common I2C LCD pinouts
-^Pin|Label|
+^Pin^Label|
 ^1|Vout|
 ^2|Cap1N|
@@ Line 76: / Line 77: @@
 Key:\\
-**VOUT**  DC/DC voltage converter. Connect a capacitor between this terminal and VIN when the built-in booster is used. , **CAP1N, CAP1P**  For voltage booster circuit(VDD-VSS) External capacitor about 0.1u~4.7uf, **VDD** 3/5V, **SDA** and **SCL** - I2C bus (I2C bus is to connect a resister between SDA/SCL and the power of I2C bus ).
+**VOUT**  DC/DC voltage converter. Connect a capacitor between this terminal and VIN when the built-in booster is used. , **CAP1N, CAP1P**  For voltage booster circuit(VDD-VSS) External capacitor about 0.1u~4.7uf, **VDD** 3/5V, **SDA** and **SCL** (also the - I2C bus lines, SDA/SCL, are open drain  and so need pullup resistors to the I2C bus power line ).
+\\
+Common SPI LCD pinouts
+^Pin^Label|
+^1|Data|
+^2|SCK|
+^3|STB|
+^4|V0|
+^5|Vdd|
+^6|Gnd|
+Key:\\
+**Data** : Serial data, **SCK** : SPI clock, **STB** : Strobe, **V0** : Contrast, **Vdd** : +3.3V or +5V, **Gnd** : Ground
+===== Determining pinout =====
+The first thing to do is determine the power supply pins.  Ground is often connected to the LCD frame.  Care should be taken if it is suspected to require a 3.3V power supply, most old LCDs only run off 5V.  If the LCD is from old equipment, examining that circuit is the easiest way to determine the power requirements.  If you just connect the power and 'contrast' supplies you will usually get a display of some character cells as solid blocks:
+{{:electronic:lcd:p4013008a.jpg?400|Power on without data or control connected}}
+If nothing is displayed while applying a 'contrast' voltage between 0 and 5V, try a negative voltage, maybe -3V to a maximum of -12V but with current limiting to a few milliamps in case you've got it wrong.  A hint that a negative supply is needed is the board having pads for and additional 8 pin IC (a charge pump negative supply).  (If the chip is actually present, then there is probably a negative supply generated on board that can be applied to the 'contrast' input.
+\\
+\\
 ====== References and Additional Resources ======
   * [[http://www.instructables.com/id/Salvaging-Liquid-Crystal-Displays-LCDs/|Salvaging and testing Liquid Crystal Displays]]
   * [[https://www.instructables.com/id/Testing-a-Graphic-LCD-Module|Testing a Graphic LCD Module]]
-===== Drivers =====
+  * [[http://forum.lcdinfo.com/|Forum supporting LCDinfo program]]
+  * [[https://web.archive.org/web/20061207084005/http://www.epemag.wimborne.co.uk/lcd1.pdf|How To Use Intelligent LCDs, part 1]]
+  * [[https://web.archive.org/web/20061207084108/http://www.epemag.wimborne.co.uk/lcd2.pdf|How To Use Intelligent LCDs, part 2]]
+===== LCD module drivers =====
+  * [[:arduino:metp0000 driver library|Driver for METP0000]], NEC µPD7225 based LCD display panel.
   * [[:arduino:uPD7228 driver library|Driver for NEC upd7228]] and uPD16434 LCD based display panels.
-  * [[arduino:t6a34_driver_library|Driver for Toshiba T6A34]] based LCD display panels
+  * [[:arduino:spilcd driver library|Driver for native SPI]] interfaced LCD display panels.
+  * [[arduino:t6a34_driver_library|Driver for Toshiba T6A34]] based LCD display panels.
   * [[https://playground.arduino.cc/Code/LCD|Arduino LCD display drivers]].
-  * [[https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/Home|New LiquidCrystal]], higher speed driver for HD44780.
+  * [[https://web.archive.org/web/20200721090823/https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/Home|New LiquidCrystal]]{{:electronic:lcd:newliquidcrystal_1.5.1.zip|,}} higher speed driver for HD44780.
-===== Datasheets =====
+===== LCD module datasheets =====
   * [[https://www.crystalfontz.com/controllers/|Collection of LCD Controller Datasheets]], data on a wide range of LCD controllers from ASLIC to Wuxi.
-  * [[http://spurtikus.de/2017/03/05/pollin-lcd-roundup/|Pollin LCD Roundup]] (German).
+  * [[https://web.archive.org/web/20250926181645/https://spurtikus.de/posts/electronics/pollin-lcd-roundup/|Pollin LCD Roundup]] (German).
-  * [[https://web.archive.org/web/20120501035512/http://www.newhavendisplay.com/index.php?main_page=app_notes|LCD controllers]]
+  * [[https://web.archive.org/web/20081226164749/http://www.av-display.com.cn/en/Products_List.aspx?menu=search&series=Character|AV-Display]] Shenzhen AV-Display Character LCDs
+  * [[https://web.archive.org/web/20210123010311/https://www.datavision.com.tw/en/lcm_01.php|Data Vision]] LCD Datasheets
+  * [[http://i-lcd.com/Downloads/LCD-Driver-Datasheets.php|IDS (Intelligent Display Solutions]] LCD Datasheets
+  * [[https://web.archive.org/web/20120501035512/http://www.newhavendisplay.com/index.php?main_page=app_notes|Newhavendisplay]] LCD controllers
+  * [[https://web.archive.org/web/*/http://sdec.com.tw/downloadfiles/*|SDEC]] Archived modules.
+  * [[https://web.archive.org/web/20240527031115/http://www.sacg.com.tw/sacweb/marcom/epaper/PDFs-new/PHILIPS-LCD%20Driver.pdf|Philips LCD controller/driver list]]
+===== LCD module naming/numbering/code scheme/systems =====
+  * {{:electronic:lcd:Shenzhen AV-Display LCM Coding System.pdf|Shenzhen AV-Display}} LCD naming system
+  * {{:electronic:lcd:data_vision_lcd_coding_system.pdf|Data Vision}} LCD naming system
+  * {{:electronic:lcd:yes_module_naming.pdf|YES Optoelectronics}} LCD naming system ((http://web.archive.org/web/20090105155758/http://yes-lcd.com/yesj/product_lcd.asp))
+===== Nokia cellphone LCDs =====
+  * [[:electronic:lcd:nokia1|Nokia 5110 cellphone and similar monochrome graphic LCDs]]
+  * [[:electronic:lcd:nokia2|Nokia cellphone colour graphic LCDs]]
+===== Ericsson cellphone LCDs =====
+  * [[:electronic:lcd:ericsson1|Ericsson cellphone graphic LCDs]]
 <html><small>If any referenced page no longer exists, try looking for its URL on <a href="http://archive.org">http://archive.org</a>.</small></html>
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