KS0066U Datasheet, PDF (7/33 Pages) Samsung semiconductor – 16COM / 40SEG DRIVER & CONTROLLER FOR DOT MATRIX LCD

KS0066U
16COM / 40SEG DRIVER & CONTROLLER FOR DOT MATRIX LCD
FUNCTION DESCRIPTION
System Interface
This chip has both kinds of interface type with MPU: 4-bit bus and 8-bit bus.
4-bit bus and 8-bit bus are selected by the DL bit in the instruction register.
During read or write operation, two 8-bit registers are used.
One is the data register (DR), and the other is the instruction register (IR).
The data register (DR) is used as a temporary data storage place for being written into or read from
DDRAM/CGRAM. The target RAM is selected by RAM address setting instruction.
Each internal operation, reading from or writing into RAM, is done automatically.
Thus, after MPU reads DR data, the data in the next DDRAM/CGRAM address is transferred into DR
automatically. Also, after MPU writes data to DR, the data in DR is transferred into DDRAM/CGRAM
automatically.
The Instruction register(IR) is used only to store instruction codes transferred from MPU.
MPU cannot use it to read instruction data.
To select a register, you can use RS input pin in 4-bit/8-bit bus mode.
Table 3. Various kinds of Operations according to RS and R/W bits
RS
R/W
Operation
L
L
Instruction Write operation (MPU writes Instruction code into IR)
L
H
Read Busy flag(DB7) and address counter (DB0 to DB6)
H
L
Data Write operation (MPU writes data into DR)
H
H
Data Read operation (MPU reads data from DR)
Busy Flag (BF)
BF = “High”, indicates that the internal operation is being processed.
So during this time the next instruction cannot be accepted. BF can be read through DB7 port
when RS = “Low” and R/W = “High” (Read Instruction Operation).
Before executing the next instruction, be sure that BF is not “High”.
Address Counter (AC)
The address Counter (AC) stores DDRAM/CGRAM addresses, transferred from IR.
After writing into (reading from) DDRAM/CGRAM, AC is automatically increased (decreased) by 1.
When RS = “Low” and R/W = “High”, AC can be read through ports DB0 to DB6.