What is this HUB75Enano

This library is a rewrite of the HUB75nano for the Arduino Nano/Uno, done in a way where it can now work with ICND2153, STP1612PW05, FM6124C and similar chipsets. This library only supports 128x64 pixel panels using one of the mentioned or similar chipsets. Biggest limitation is the tiny 2kB SRAM of the ATM368p, it just barely fits enough pixels in there :D.

Usage

To use this library, either aqcuire it using the Arduino Library Manager or download the repository as a zip file, then place it in your custom library folder. Some examples are provided, see the examples folder or the examples section in the Arduino IDE.

How to connect your panel to the nano

Here is a table describing the pin, and what it is used for. You should connect at least one ground wire.

HUB75E Connector	arduino pin
R1	D2
G1	D3
B1	D4
GND	GND/n.C
R2	D5
G2	D6
B2	D7
n.C	A4
A	A0
n.C	A1
C	A2
n.C	A3
CLK	D9
LAT	D10
OE	D11
GND	GND/n.C

If your panel actually uses all A,B,C,D and E pins for row adressing, but your chipset is compatible, you may #define the PANEL_5_PIN_ROWS constant and use it that way.

Settings

The panel has some different modes of operation and ways of configuring it, see the table below

Constant name	function	default	more info
PANEL_X	defines the internal width of the buffer for the panel, don't change or things can break.	64	Note: not the actual size of the panel, as it turns 2x2 real pixels into one for disply/output
PANEL_Y	defines the internal height of the buffer for the panel, don't change or else things can break.	32	Note: not the actual size of the panel, as it turns 2x2 real pixels into one for disply/output
PANEL_BIG	Provides a 2bit rgb buffer for the panel in SRAM.	-	Utilizes about 1.6kB of the 2Kb RAM
PANEL_FLASH	Provides a 4bit rgb buffer for the panel in Flasj.	-	Each image in Flash utilizes exactly 4 bytes, the output function takes about 13Kb. utilizes nearly no SRAM.
PANEL_NO_BUFFER	No buffer, immediate mode only. Useful if you only want to use the Panel in a single color, you get many CPU cycles and nearly all ram back	-
PANEL_GPIO_NON_INTRUSIVE	Changes some functions so the library doesn't overwrite the other pins in GPIOB/PORTB	-	By default, the whole PORTB (D8-D13) are set at once and are unusable, even though we need only D9-11. Enabling this increases the filesize by some 6kB and reduces the Panel refresh rate
PANEL_SMALL_BRIGHT	The display appears much brighter but it has some slight ghosting in black areas	-
PANEL_ENABLE_FLASH_EDIT	Enables editing the flash during runtime	-	NOT YET IMPLEMENTED
PANEL_5_PIN_ROW	Switches row adressing from shift registers to direct multiplexed adressing	-	Activate this when your panel chips match the ones for this library, but your row adressing doesn't work/doesn't use shift registers but demultiplexers
PANEL_NO_FONT	Removes all font related things from the compilation, can save flash space	-
PANEL_HIGH_RES	Reworks the panel to work in a 64x64 high resolution mode, window at center	-	the flash buffer is only available in the 1 bit version, and the images for the flash buffer have to be generated with the 64x64 size tag, see BMP2HUB75

Example

This here is the small buffer example and it's output.

// uncomment the line below to increase the brightness of the image, will poroduce some minor ghosting then though.
// #define PANEL_SMALL_BRIGHT
#include <Arduino.h>
// inlcude the library
#include "HUB75Enano.h"

// create an instance of the panel
Panel panel = {};

// runs once, we set up the image here
void setup()
{
    // draws the shapes onto the buffer, which is then displayed on the led matrix
    // panel.fillBuffer(panel.BLACK);
    panel.drawSquare(63, 1, 0, panel.CYAN, true);
    panel.drawRect(0, 0, 5, 31, panel.YELLOW, true);    // yellow filled rectangle top left
    panel.drawRect(25, 16, 29, 23, panel.GREEN, false); // green hollow rectangle somewhere in the middle
    panel.drawLine(6, 0, 63, 31, panel.WHITE);          // white diagonal through nearly the whole frame
    panel.drawCircle(50, 10, 5, panel.BLUE, false);     // hollow blue circle top right
    panel.drawCircle(11, 25, 5, panel.RED, true);       // filled cyan circle bottom left
    panel.drawEllipse(30, 6, 6, 3, panel.GREEN, false);
    panel.drawEllipse(61, 19, 2, 7, panel.PURPLE, true);
    panel.drawChar(7, 12, 'b', panel.PURPLE);
    panel.drawSquare(0, 0, 2, panel.RED, true);
    panel.drawSquare(0, 8, 2, panel.GREEN, true);
    panel.drawSquare(0, 16, 2, panel.BLUE, true);
}

// runs forever after setup
void loop()
{
    // output the buffer to the screen in a loop
    panel.displayBuffer();
}

More images

big buffer, 2 bit SRAM buffer

4 bit flash

high res SRAM buffer

high res flash buffer

Further info

The datasheet for the STP1612PW05 is the most informative and is also applicable to at least the FM6124C and ICND2153.

I also made a writeup on the control logic here