MC80F0424 Datasheet, PDF (82/135 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

MC80F0424/0432/0448
Preliminary
16. SERIAL INPUT/OUTPUT (SIO)
The serial Input/Output is used to transmit/receive 8-bit data se-
rially. The Serial Input/Output(SIO) module is a serial interface
useful for communicating with other peripheral of microcontrol-
ler devices. These peripheral devices may be serial EEPROMs,
shift registers, display drivers, A/D converters, etc. This SIO is 8-
bit clock synchronous type and consists of serial I/O data register,
serial I/O mode register, clock selection circuit, octal counter and
control circuit as illustrated in Figure 16-1. The SO pin is de-
signed to input and output. So the Serial I/O(SIO) can be operated
with minimum two pin. Pin R42/SCK, R43/SI, and R44/SO pins
are controlled by the Serial Mode Register. The contents of the
Serial I/O data register can be written into or read out by software.
The data in the Serial Data Register can be shifted synchronously
with the transfer clock signal.
X_IN PIN
Timer0
Overflow
SCK PIN
SO PIN
SIOST
SIOSF
SCK[1:0]
÷4
00
÷ 16
01
10
11
“11” _MUX
not “11”
SCK[1:0]
SM0
POL
“0”
“1”
IOSW
Start
Complete
SIO
Clock ^CONTROL
CIRCUIT
Clock
SOUT
clear
overflow
Octal
Counter
(3-bit)
SIOIF
Serial communication
Interrupt
IOSW
1
SI PIN
0
Input shift register
Shift
SIOR
Internal Bus
Figure 16-1 SIO Block Diagram
78
MAR. 2005 Ver 0.2