MagnaChip MC80F0104, User Manual, Page: 71 / 126

Preliminary MC80F0104/0204
Mar. 2005 Ver 0.2 67
15. SERIAL INPUT/OUTPUT (SIO)
The serial Input/Output is used to transmit/receive 8-bit
data serially. The Serial Input/Output (SIO) module is a se-
rial interface useful for communicating with other periph-
eral of microcontroller 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 15-1 . The SO pin is designed
to input and output. So the Serial I/O(SIO) can be operated
with minimum two pin. Pin R00/SCK, R01/SI, and R02/
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 Regis-
ter can be shifted synchronously with the transfer clock
signal.
Figure 15-1 SIO Block Diagram
÷
4
÷
16
X
IN
PIN
P
res
caler
MUX
SCK[1:0]
00
01
10
11
SCK PIN
SIO
Shift
Input shift register
SIOR
Clock
Clock
Octal
Serial communication
Interrupt
SIOIF
Internal Bus
SIOSF
Counter
SCK[1:0]
“11”
overflow
not “11”
Complete
Timer0
Overflow
SI PIN
IOSW
SO PIN
SOUT
IOSW
CONTROL
CIRCUIT
“0”
“1”
POL
1
0
Start
SIOST
clear
SM0
(3-bit)