MC80F0204 Datasheet, PDF (74/126 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

MC80F0104/0204
Preliminary
15.2 The usage of Serial I/O
1. Select transmission/receiving mode.
2. In case of sending mode, write data to be send to SIOR.
3. Set SIOST to “1” to start serial transmission.
4. The SIO interrupt is generated at the completion of SIO
and SIOIF is set to “1”. In SIO interrupt service routine,
correct transmission should be tested.
5. In case of receiving mode, the received data is acquired
by reading the SIOR.
LDM
SIOR,#0AAh
;set tx data
LDM
SIOM,#0011_1100b ;set SIO mode
NOP
LDM
SIOM,#0011_1110b ;SIO Start
Note: When external clock is used, the frequency should be less
than 1MHz and recommended duty is 50%. If both transmission
mode is selected and transmission is performed simultaneously,
error may be occur.
15.3 The Method to Test Correct Transmission
Serial I/O Interrupt
Service Routine
0
SIOSF
1
SIOE = 0
Abnormal
Write SIOM
0
SIOIF
1
Normal Operation
Overrun Error
- SIOE: Interrupt Enable Register High IENH(Bit1)
- SIOIF: Interrupt Request Flag Register High IRQH(Bit1)
Figure 15-5 Serial IO Method to Test Transmission
70
Mar. 2005 Ver 0.2