GMS81C5108 Datasheet, PDF (66/102 Pages) Hynix Semiconductor – HYNIX SEMICONDUCTOR INC. 8-BIT SINGLE-CHIP MICROCONTROLLERS

GMS81C5108
To accomplish communication, typically three pins are
used:
- Serial Data In
- Serial Data Out
- Serial Clock
R07/SI
R06/SO
R05/SCK
The serial data transfer operation mode is decided by set-
ting the SIO1 and SIO0 and the transfer clock rate is decid-
ed by setting the SICK1 and SICK0 of SCI Mode Control
Register as shown in Figure 16-1. And the polarity of
transfer clock is selected by setting the POL. The MSBS
bit is used to select which bit would be sending or receiv-
ing.
SIO1
0
0
1
1
SIO0
0
1
0
1
Function Selection
-
Transmit Mode
Receive Mode
Transmit and Receive
Port Selection
R05/SCK R06/SO R07/SI
R05
R06
R07
SCK
SO
R07
SCK
R06
SI
SCK
SO
SI
16.1 Data Transmit/Receive Timing
The SCI operation is executed by setting the SIOST bit to
“1”. The SIOST bit is cleared to “0” automatically after 1
machine cycle. The Serial output data is shift in or shift out
at edge decided by POL. Interrupt is occurred when the
eight in/out datas is counted by octal counter.
MSBS=0
SIOST
R05/SCK
(POL=1)
R05/SCK
(POL=0)
R06/SO
R07/SI
SIOSF
SIOIF
(SCI Int. Req)
D0
D1
D2
D3
D4 D5
D6
D7
D0
D1
D2
D3
D4
D5
D6
D7
Figure 16-2 SCI Timing Diagram
JUNE 2001 Ver 1.0
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