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User’s Manual U15104EJ2V0UD
CHAPTER 11 SERIAL INTERFACES SIO30 TO SIO32
11.1 Functions of Serial Interfaces SIO30 to SIO32
The serial interface SIO3n has the following two modes.
(1) Operation stop mode
This mode is used when serial transfer is not performed. For details, refer to 11.4.1 Operation stop mode.
(2) 3-wire serial I/O mode (MSB first)
In this mode, 8-bit data is transferred by using three lines: serial clock (SCK3n), serial output (SO3n), and
serial input (SI3n) lines.
Because transmission and reception can be executed simultaneously in this mode, the processing time of data
transfer can be shortened.
The first bit of the 8-bit data to be transferred is the MSB.
The 3-wire serial I/O mode is useful for connecting a peripheral I/O or display controller with a clocked serial
interface. For details, refer to 11.4.2 3-wire serial I/O mode.
Figures 11-1 to 11-3 show the block diagrams of the serial interface SIO3n.
Remark
n = 0 to 2
Figure 11-1. Block Diagram of Serial Interface SIO30
Internal bus
8
Interrupt
request signal
generator
Selector
Serial clock
counter
Serial clock
controller
Serial I/O shift
register 30 (SIO30)
SI30/P70
SO30/P71
P71 output latch
PM71
PM72
SCK30/P72
INTCSI30
f
X
/2
4
f
X
/2
5
f
X
/2
6
P72 output latch
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