EM65101
128COM/160SEG 16 Gray Scale Level LCD Driver
7.1.5 Serial Interface
The EM65101 has two types of serial interfaces, i.e., 3-wire or 4-wire serial interface.
Use the SMODE pin to select the serial interface type.
SMODE = “L”: 4-wire serial interface
SMODE = “H”: 3-wire serial interface
7.1.5.1 4-Wire Serial Interface
When chip select is active (CSB = “L”), 4-wires type serial interface works through the
SDA and SCL input pins. When chip select is inactive (CSB = “H”), the internal shift
register and counter are reset to the initial condition. Serial data SDA are input
sequentially in the order of D7 to D0 at the rising edge of the serial clock (SCL). The RS
pin determines whether serial data input (SDA) is used as display RAM data or as
control register data.
RS = “L”: display RAM data
RS = “H”: register control data
After completing the 8-bit data transfer, or when making no access, be sure to set the
serial clock input (SCL) to “L.” Care should be taken during PCB layout to avoid
external noise from contaminating the SDA and SCL signals. To prevent any transfer
error due to external noise, release chip select (CSB = “H”) after every complete 8-bit
data transfer.
CSB
RS
D7
D6
D5
D4
D3
D2
D1
D0
SDA
SCL
1
2
3
4
5
6
7
8
Figure 7-2 4-Wire Serial Interface
7.1.5.2 3-Wire Serial Interface
When chip select is active (CSB = “L”), 3-wire serial interface works through the SDA
and SCL input pins. When chip select is inactive (CSB = “H”), the internal shift register
and counter are reset to the initial condition. Serial data SDA are input sequentially in
the order of RS, D7 to D0 at the rising edge of the serial clock (SCL). The first serial
input data (RS) and the SPOL pin determine whether serial data input (SDA) is used as
display RAM data or as control register data.
14 •
Product Specification (V0.4) 08.15.2005
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
