
HYUNDAI MicroElectronics
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2.9.3. The method of Serial I/O
Select transmission/receiving mode
<Notice> When external clock is used, the frequency should be less than 1MHz and
recommended duty is 50%.
In case of sending mode, write data to be send to SIOR.
Set SIOST to
“
1
”
to start serial transmission.
<Notice > If both transmission mode is selected and transmission is performed simultaneously
it would be made error.
The SIO interrupt is generated at the completion of SIO and SIOSF is set to
“
1
”
. In SIO
interrupt service routine, correct transmission should be tested.
In case of receiving mode, the received data is acquired by reading the SIOR.
2.9.4. The Method to Test Correct Transmission with S/W
Serial I/O Interrupt
Service Routine
SIOSF
SE=0
Write SIOM
Normal Operation
Overrun Error
SR
Abnormal
0
0
1
1
Serial Method to Test Transmission.
Note) SE: Interrupt Enable Regist Low IENL ( Bit3 )
SR : Interrupt Request Flag Regist Low IRQL ( Bit3 )