HD404818 Datasheet, PDF (58/100 Pages) Hitachi Semiconductor – 16-digit LCD driver

HD404818 Series
Serial Interface
The serial interface transmits/receives 8-bit data serially. It consists of the serial data register, the serial
mode register, port mode register A, the octal counter, and the selector (figure 29). Pin R0₀/SCK and the
transmit clock signal are controlled by the serial mode register. The data of the serial data register can be
written and read by software. The data in the serial data register can be shifted synchronously with the
transmit clock signal.
The STS instruction starts serial interface operations and resets the octal counter to $0. The octal counter
starts to count at the falling edge of the transmit clock signal (SCK) and increments by one at the rising
edge of the SCK. When the octal counter is reset to $0 after eight transmit clock signals, or when a
transmit/receive operation is discontinued by resetting the octal counter, the serial interrupt request flag will
be set.
SO
SCK
SI
I/O
control
logic
I/O
control
logic
Octal
counter (OC)
Clock
1/2
Serial interrupt
request flag
(IFS)
Serial data
register (SR)
Transfer
control
signal
System ^fcyc/fsub
clock _{(tcyc/tsubcyc)}
Selector
3
Serial mode
register
(SMR)
Prescaler S (PSS)
Port mode
register
(PMRA)
Figure 29 Serial Interface Block Diagram
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