Data Sheet

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7-3-1-3) MCU Serial Interface (3-wire SPI)
The 3-wire serial interface consists of serial clock SCLK, serial data SDIN and CS#.
In 3-wire SPI mode, D0 acts as SCLK, D1 acts as SDIN, The pin D/C# can be connected to an external ground.
The operation is similar to 4-wire serial interface while D/C# pin is not used. There are altogether 9-bits will be shifted into the shift
register on every ninth clock in sequence: D/C# bit, D7 to D0 bit. The D/C# bit (first bit of the sequential data) will determine the following
data byte in shift register is written to the Display Data RAM (D/C# bit = 1) or the command register (D/C# bit = 0).Under serial mode,
only write operations are allowed.
Function
CS#
D/C#
SCLK
Write Command
L
Tie LOW
↑
Write data
L
Tie LOW
↑
Table 7-4-1-3: Control pins of 3-wire Serial Peripheral Interface
Note 7-5: ↑stands for rising edge of signal
Figure 7-4-1-3: Write procedure in 3-wire Serial Peripheral Interface mode