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Revision to Connecting an LCD control panel

Ian A-S

== Connecting a 12864 mono graphics LCD display with rotary encoder ==
-There are two types of controller chip commonly used in these controllers: ST7920 and ST7567. Some Duets support one or both of these types - see later for details. Both types use a menu system stored on the SD card, see [[Duet 2 Maestro 12864 display menu system]].
-
-=== 12864 display using ST7920 controller chip ===
-
-[image|2928|align=right]
-
-These displays are typically clones of the [https://reprap.org/wiki/RepRapDiscount_Full_Graphic_Smart_Controller|RepRapDiscount Full Graphic Smart Controller] and look like this. The better ones include a contrast adjustment potentiometer. Unfortunately some manufacturers of other displays using the same controller chip reverse the pinouts on the two ribbon cable connectors. The ST7920 controller chip is invariably powered from 5V, which means that the display need 5V input signal levels.
-
-To configure this type of display in RepRapFirmware, use the [[Gcode#Section_M918_Configure_direct_connect_display|M918 command]] with display type parameter P1.
-
-=== 12864 display using ST7567 controller chip ===
-
-An example of this is the [https://wiki.fysetc.com/Mini12864_Panel|Fysetc Mini 12864 Panel]. The controller chip is run from 3.3V, so these displays normally include level shifters which tolerate a wide range of input voltages.
-
-To configure this type of display in RepRapFirmware, use the [[Gcode#Section_M918_Configure_direct_connect_display|M918 command]] with display type parameter P2.
-
-The contrast setting for these displays is done in software. the M918 command supports a C parameter for this purpose. It is also necessary to set a resistor ratio parameter in software, which can be done using the M918 R parameter.
+There are two types of controller chip commonly used in these controllers: ST7920 and ST7567. Some Duets support one or both of these types - see below for details. Both types use a menu system stored on the SD card, see [[Duet 2 Maestro 12864 display menu system]].
=== Compatibility matrix ===
}
+=== 12864 display using ST7920 controller chip ===
+
+[image|2928|align=right]
+
+These displays are typically clones of the [https://reprap.org/wiki/RepRapDiscount_Full_Graphic_Smart_Controller|RepRapDiscount Full Graphic Smart Controller] and look like this. The better ones include a contrast adjustment potentiometer. Unfortunately some manufacturers of other displays using the same controller chip reverse the pinouts on the two ribbon cable connectors. The ST7920 controller chip is invariably powered from 5V, which means that the display need 5V input signal levels.
+
+To configure this type of display in RepRapFirmware, use the [[Gcode#Section_M918_Configure_direct_connect_display|M918 command]] with display type parameter P1.
+
+=== 12864 display using ST7567 controller chip ===
+
+An example of this is the [https://wiki.fysetc.com/Mini12864_Panel|Fysetc Mini 12864 Panel]. The controller chip is run from 3.3V, so these displays normally include level shifters which tolerate a wide range of input voltages.
+
+To configure this type of display in RepRapFirmware, use the [[Gcode#Section_M918_Configure_direct_connect_display|M918 command]] with display type parameter P2.
+
+The contrast setting for these displays is done in software. the M918 command supports a C parameter for this purpose. It is also necessary to set a resistor ratio parameter in software, which can be done using the M918 R parameter.
+
=== Duet 3 Mini 5+ support for 12864 displays ===
-Duet 3 Mini provides two 2x5 ribbon cable headers for connecting a Fysetc 12864 Mini Panel version 1.2 or 2.1 ('''not 2.0''') or compatible controller. When using a version 2.1 controller, the colours of the three Neopixel LEDs built into the display can be set using the M150 command with LED type parameter X2.
+Duet 3 Mini provides two 2x5 ribbon cable headers for connecting a Fysetc 12864 Mini Panel version 1.2 or 2.1 ('''not 2.0''') or compatible ST7567-based controller. When using a version 2.1 controller, the colours of the three Neopixel LEDs built into the display can be set using the M150 command with LED type parameter X2.
We do not recommend connecting a 12864 display with ST7920 controller to the Duet 3 Mini because the 3.3V signals provided by the Duet 3 Mini do not meet the specifications of the ST7920 controller chip when it is powered from 5V. If you do wish to try it, you will most likely have to reduce the clock frequency (M918 F parameter) to get it working at all, and it may not work reliably. Also, note that when configured for 12864 display with ST7920 controller, RRF provides the CS signal on the pin normally uses for A0 because that more closely matched the pinout of typical 12864/ST7920 displays.

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