GMS81C2012 Datasheet, PDF (68/107 Pages) Hynix Semiconductor – HYUNDAI MICRO ELECTRONICS 8-BIT SINGLE-CHIP MICROCONTROLLERS

GMS81C2012/GMS81C2020
HYUNDAI MicroElectronics
14.2 The method of Serial I/O
 Select transmission/receiving mode
Note: 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.
Note: If both transmission mode is selected and transmis-
sion 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.
14.3 The Method to Test Correct Transmission
Serial I/O Interrupt
Service Routine
0
SIOSF
1
SE = 0
Abnormal
Write SIOM
0
SR
1
Normal Operation
Overrun Error
- SE : Interrupt Enable Register Low IENL(Bit3)
- SR : Interrupt Request Flag Register Low IRQL(Bit3)
Figure 14-5 Serial Method to Test Transmission
68
MAR. 2000 Ver 1.00