GMS81C5108
16.2 The method of Serial I/O
1. Select transmission/receiving mode
If both transmission mode is selected and transmission is per-
formed simultaneously it would be made error.
When external clock is used, the frequency should be less than
1MHz and recommended duty is 50%.
4. The SIO interrupt is generated at the completion of SIO and
SIOSF is set to “1”.
2. In case of sending mode, write data to be send to SIOD.
3. Set SIOST to “1” to start serial transmission.
5. In case of receiving mode, the received data is acquired by
reading the SIOD.
SIOST
SCLK [R05]
(POL=1)
D0
D1
D2
D3
D4
D5
D6
D7
SOUT [R06]
SIN [R07]
D0
D 1
D 2
D 3
D 4
D 5
D 6
D 7
SIOSF
SIOIF
Figure 16-3 SCI Timing Diagram at POL=1
64
JUNE 2001 Ver 1.0
HYNIX [ HYNIX SEMICONDUCTOR ]
