Pin	Symbol	Level	Descripition
1	Vss	0V	Ground
2	Vdd	5.0V	Supply Voltage for Logic
3	VO	(variable)	Operating voltage for LCD
4	RS	H/L	H: DATA, L: Instruction code
5	R/W	H/L	H: Read(MPU->Module) L: Write(MPU->Module)
6	E	H,H->L	Chip enable signal
7	Data 0	H/L	Data bit 0
8	Data 1	H/L	Data bit 1
9	Data 2	H/L	Data bit 2
10	Data 3	H/L	Data bit 3
11	Data 4	H/L	Data bit 4
12	Data 5	H/L	Data bit 5
13	Data 6	H/L	Data bit 6
14	Data 7	H/L	Data bit 7
15	A	-	LED+
16	K	-	LED-

LCD Character Locations

Location	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20
Address	00	01	02	03	04	05	06	07	08	09	0A	0B	0C	0D	0E	0F	10	11	12	13
Address	40	41	42	43	44	45	46	47	48	49	4A	4B	4C	4D	4E	4F	50	51	52	53

Function

The LCD display Module is built in a LSI controller, the controller has two 8-bit registers, an instruction register (IR) and a data register (DR). The IR stores instruction codes, such as display clear and cursor shift, and address information for display data RAM (DDRAM) and character generator (CGRAM). The IR can only be written from the MPU. The DR temporarily stores data to be written or read from DDRAM or CGRAM. When address information is written into the IR, then data is stored into the DR from DDRAM or CGRAM. By the register selector (RS) signal, these two registers can be selected.

RS	R/W	Operation
0	0	IR write as an internal operation (display clear, etc.)
0	1	Read busy flag (DB7) and address counter (DB0 to DB7)
1	0	Write data to DDRAM or CGRAM (DR to DDRAM or CGRAM)
1	1	Read data from DDRAM or CGRAM (DDRAM or CGRAM to DR)