I posted about the All Electronics LCD-101 display in February 2018. The other day, I noticed that they were back in stock, so I decided to dust off where I last left off with the display. I had designed an I2C backpack with a contrast voltage driver for the display and modified the test Arduino code that I had to work with the backpack. The code was incomplete, so I needed to pick up where I left off, start over, or look at extending another library. I did look at the U8g2 library (https://github.com/olikraus/U8g2_Arduino) but it does not work well with the display. It may be because it is expecting the display to be 240 x 128 rather than 256 x 128.

LCD Pins

Pin No.	Symbol	Level	Function	JP2 Pin	I2C bit
1	FG	0V	Frame Ground	1	N/A
2	Vss(Gnd)	0V	Ground	1	N/A
3	Vdd(Vcc)	+5V	Power supply voltage for logic and LCD	2	N/A
4	Vo	–	Operating voltage for LCD (variable)	N/A	N/A
5	/RES	H/L	Reset signal	3	A0
6	/RD	H/L	Read signal	4	A1
7	/WR	H/L	Write signal	5	A2
8	/CS	H/L	Chip select signal	6	A3
9	A0	H/L	Data type select signal	7	A4
10	DB0	H/L	Display data bit 0	8	B0
11	DB1	H/L	Display data bit 1	9	B1
12	DB2	H/L	Display data bit 2	10	B2
13	DB3	H/L	Display data bit 3	11	B3
14	DB4	H/L	Display data bit 4	12	B4
15	DB5	H/L	Display data bit 5	13	B5
16	DB6	H/L	Display data bit 6	14	B6
17	DB7	H/L	Display data bit 7	15	B7

A0	/CS	/WR	/RD	/RES
I2C A4	I2C A3	I2C A2	I2C A1	I2C A0	Binary MASK	HEX	Decimal	Valid Op	Valid Result	Function/Note
X	X	X	X	0	11110	0x1E	30	OR	11110	Reset
X	0	0	0	1	01111	0x0F	15	AND	00001	Invalid State
X	0	1	1	1	01111	0x0F	15	AND	00111	No Operation
X	1	X	X	1	01001	0x09	9	AND	01001	No Operation
0	0	0	1	1	00011	0x03	3	EQUAL/XOR	00011	Display data and parameter write
0	0	1	0	1	00101	0x05	5	EQUAL/XOR	00101	Status flag read
1	0	0	1	1	10011	0x13	19	EQUAL/XOR	10011	Command write
1	0	1	0	1	10101	0x15	21	EQUAL/XOR	10101	Display data and cursor address read

A0	/CS	/WR	/RD	/RES	Mask				Valid Result
A4	A3	A2	A1	A0	Binary	HEX	Decimal	Valid Op	Binary	HEX	Decimal	Function/Note
X	X	X	X	0	11110	0x1E	30	OR	11110	0x1E	30	Reset
X	0	0	0	1	01111	0x0F	15	AND	00001	0x01	1	Invalid State
X	0	1	1	1	01111	0x0F	15	AND	00111	0x07	7	No Operation
X	1	X	X	1	01001	0x09	9	AND	01001	0x09	9	No Operation
0	0	0	1	1	00011	0x03	3	EQUAL/XOR	00011	0x03	3	Display data and parameter write
0	0	1	0	1	00101	0x05	5	EQUAL/XOR	00101	0x05	5	Status flag read
1	0	0	1	1	10011	0x13	19	EQUAL/XOR	10011	0x13	19	Command write
1	0	1	0	1	10101	0x15	21	EQUAL/XOR	10101	0x15	21	Display data and cursor address read

12 June 2022 Update

I had a question about this display, so I have updated the GitLab repository at https://gitlab.com/richteel/LCD-101/ to include the I2C Backpack that I designed for the LCD with a negative charge pump for the contrast and I2C or SPI interface for Arduino and Raspberry Pi. You may order the black PCB from Oshpark at https://oshpark.com/shared_projects/LwLCCjaW.

The schematic for the backpack is in the LCD-101/LCD-101 2020/I2C Backpack folder and is named I2C Backpack.pdf.

12 June 2022 Update

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By richteel