Displaytech 164G FC BW-3LP

This LCD module has a built-in LSI controller containing two 8-bit registers: an Instruction Register (IR) and a Data Register (DR). The IR stores instruction codes (such as display clear and cursor move) as well as address information for the Display Data RAM (DDRAM) and Character Generator RAM (CGRAM). The IR can only be written by the MPU. The DR temporarily stores data to be written to or read from DDRAM or CGRAM. When address information is written to the IR, data is transferred from DDRAM or CGRAM into the DR. These two registers are selected via the Register Select (RS) signal. When the Busy Flag (BF) is 1, it indicates that the controller LSI is in internal operation mode and will not accept the next instruction. When RS=0 and R/W=1, the busy flag is output to DB7. The next instruction must not be written until the busy flag is confirmed to be 0. The Address Counter (AC) assigns addresses to DDRAM and CGRAM. The DDRAM stores display data in 8-bit character codes, with an extended capacity of 80×8 bits or 80 characters. The Character Generator ROM (CGROM) generates 5×8-dot or 5×10-dot character patterns from 8-bit character codes. The Character Generator RAM (CGRAM) allows users to reprogram character patterns — up to eight patterns for 5×8-dot format and four patterns for 5×10-dot format. Character patterns stored in CGRAM can be displayed by writing the character codes corresponding to the addresses shown in the left column of Table 1 into DDRAM.