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ERM19264

ERM19264_UC1609_RPI

Table of contents

Overview

  • Name : ERM19264_UC1609_RPI
  • Title : Library for ERM19264-5 v3 LCD (UC1609C controller)
  • Description :
  1. Dynamic install-able system level Raspberry Pi C++ library.
  2. Inverse, Scroll, rotate and contrast control.
  3. 6 standard ASCII font + glyph font support
  4. Graphics class included.
  5. Sleep mode.
  6. Bitmaps supported.
  7. Hardware & software SPI options
  8. Dependency: bcm2835 Library
  9. See also : Combined Display library 'Display_Lib_RPI'

  • Author: Gavin Lyons

  • This is a port of my Arduino library More details there as well as link to the API(There are some differences between this port and Arduino library most notably use of glyph fonts)

  • Development Tool chain.

    1. Raspberry PI 3 model b
    2. C++, g++ (Debian 12.2.0)
    3. Raspbian , Debian 12 bookworm OS, , 64 bit.
    4. kernel : aarch64 Linux 6.1.0-rpi7-rpi-v8
    5. bcm2835 Library 1.73 dependency. Provides low level I2C bus, delays and GPIO control.

Output

Output Screenshots, From left to right top to bottom.

  1. Full screen bitmap displayed
  2. FPS example test.
  3. Different size and inverted ASCII fonts.
  4. ASCII font 0-127 printed out (128-255 also available)
  5. Glyph fonts

op op

Installation

  1. Install the dependency bcm2835 Library if not installed (at time of writing latest version is 1.73)

    • The bcm2835 library is a dependency and provides SPI bus, delays and GPIO control.
    • Install the C libraries of bcm2835, Installation instructions here

  2. Download the ERM19264_UC1609_RPI library

    • Open a Terminal in a folder where you want to download,build & test library
    • Run following command to download from github.
curl -sL https://github.com/gavinlyonsrepo/ERM19264_UC1609_RPI/archive/1.7.1.tar.gz | tar xz
  1. Run "make" to run the makefile to install library, it will be installed to usr/lib and usr/include
cd ERM19264_UC1609_RPI-1.7.1
make
sudo make install

Test

  1. Next step is to test LCD and installed library with an example. Wire up your LCD. Next enter the examples folder and run the makefile in THAT folder, This makefile builds the examples file using the just installed library. and creates a test exe file in "bin". User should see "hello world" on the LCD screen by end of this step.
cd examples/
make
make run
  1. There are seven examples files to try out. To decide which one the makefile builds simply edit "SRC" variable at top of the makefile in examples folder. In the "User SRC directory Option Section". Pick an example "SRC" directory path and ONE ONLY. Comment out the rest and repeat step 1.

Hardware

9 pins , Vcc and GND, anode and cathode for the backlight LED and an SPI interface. The backlight control is left up to user , connect to 3.3V thru a resistor. If using Hardware SPI 3 pins will be tied to the SPI CEO, CLK and MOSI lines. if using software SPI you should be able use any GPIO you want for all five pins. Datasheets URLS are in the extras folder.

There are 3 different colours in range, Parts used purchased from ebay

  1. ERM19264SBS-5 V3 LCD Display UC1609C controller , white on blue
  2. ERM19264FS-5 V3 LCD Display UC1609C controller , black on white
  3. ERM19264DNS-5 V3 LCD Display UC1609C controller white on black

Wiring Diagram from supplier showing connection to RPI.

ERM19264

This wiring Diagram from the manufacturer showing hardware setup connected to an ~8051 MCU, showing both 3.3 volt and 5 volt systems. Note status of J1 PCB jumper.

ERM192642

Software

SPI

Hardware and software SPI. Two different class constructors. User can pick the relevant constructor, see examples files. Hardware SPI is recommended, far faster and more reliable but Software SPI allows for more flexible GPIO selection. When running Software SPI it may be necessary on very high frequency MCU's to change the LCD_HighFreqDelaySet method, It is a microsecond delay by default it is at 0.

The SPI settings are in LCDSPIon function. Speed is currently at BCM2835_SPI_CLOCK_DIVIDER_64. 6.25MHz on RPI3. This can be adjusted in code or user can pass the divider value in the "begin" method as a parameter. These values are defined by enum bcm2835SPIClockDivider. For full list see link. User can also adjust which SPI chip enable pin the use uing "begin" method parameter.

Fonts

There are 6 standard scale-able ASCII fonts. A print class is available to print out most passed data types. The fonts 1-6 are byte high(at text size 1) scale-able fonts, columns of padding added by SW. The example file TEXT_GRAPHICS shows how to use these.

Six standard fonts available :

Font num Font name Font size xbyy Note
1 Default 5x8 Full Extended ASCII 0 - 0xFF
2 Thick 7x8 no lowercase letters , ASCII 0x20 - 0x5A
3 Seven segment 4x8 ASCII 0x20 - 0x7A
4 Wide 8x8 no lowercase letters, ASCII 0x20 - 0x5A
5 Tiny 3x8 ASCII 0x20 - 0x7E
6 Homespun 7x8 ASCII 0x20 - 0x7E

In addition to those 6 fonts, The ability to use glyph-fonts is also available. I have packaged four fonts with the library, these are not installed in the system but are in the include folder of examples. The example file FONTS_GLYPH shows how to use these. The Font structures are in the ERM19264_gfxfont.h file. To use a font in your program, #include the corresponding .h file and pass address of GFXfont struct to setFont(). Other fonts are available from the Adafruit GFX arduino library. If you copy over other fonts remove the PROGMEM keyword. Lots more detail there on how these fonts are created and work. The glyph-fonts use 3 special functions: setFontGlyph drawCharGlyph drawTextGlyph. They cannot currently use the print class, also cannot be inverted. Inverting only works with the standard fonts because the characters are a uniform size. It's not a sensible thing to do with proportionally-spaced fonts with glyphs of varying sizes and that may overlap.

Bitmaps

There is a few different ways of displaying bitmaps,

Num Method Data addressing Note
1 LCDBitmap() Vertical Writes directly to screen , no buffer used.
2 LCDBuffer() Vertical For internal use mostly
3 buffer init Vertical Can be used when initialising at start up
4 drawBitmap() Vertical default, setDrawBitmapAddr(true)
5 drawBitmap() Horizontal setDrawBitmapAddr(false)

See the bitmap example file for more details on each method. Bitmaps can be turned to data here at link , Bitmaps should be defined as const buffers non-const, for methods 3 buffer can be initialised with bitmap data.

User Adjustments

If the LCD does not initialize correctly. Try adjusting the RAM address control setting from 0x02 to 0x01. It can be set in LCDbegin() argument list. See github issue 4 at the Arduino source port github repository for more details, link in overview.

When the user calls LCDbegin() to start LCD they can specify a contrast setting from 0x00 to 0xFF. Datasheet says 0x49 is default. (VbiasPOT). Lower contrast works better on the blue color version.

It is also possible for user to change LCD bias , Temperature coefficient, frame rate and power control but this must be done by changing defines in header file. Choose lower frame rate for lower power, and choose higher frame rate to improve LCD contrast and minimize flicker. See Data sheet for range of values here. Defaults where found to be fine during all testing of this library.

Parameter default Values Define Register Bits
LCD bias 9 BIAS_RATIO_SET BR 1:0
Temp coefficient -0.00%/ C TEMP_COMP_SET TC 1:0
Frame rate 95 fps FRAMERATE_SET LC 4:3
Power control 1.4mA + Internal VLCD (7x charge pump) PC_SET PC 2:0
V bias Bot(contrast) 0x49 Set by user with LCDbegin PM 7:0
Ram Address Control 0x02 Set by user with LCDbegin AC 2:0

Notes and Issues