MC80F0424 Datasheet, PDF (85/135 Pages) List of Unclassifed Manufacturers – 8-BIT SINGLE-CHIP MICROCONTROLLERS

Preliminary
MC80F0424/0432/0448
16.2 The method 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 per-
formed simultaneously, error will be made.
16.3 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(Bit3)
- SIOIF: Interrupt Request Flag Register High IRQH(Bit3)
Figure 16-5 Serial IO Method to Test Transmission
MAR. 2005 Ver 0.2
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