M38002M4 Datasheet, PDF (80/173 Pages) Mitsubishi Electric Semiconductor – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
2.3 Serial I/O
Transmitting side
Serial I/O status register (Address : 1916)
b7
b0
SIOSTS
Transmit buffer empty flag
• Check to be transferred data from the Transmit buffer register to
Transmit shift register.
• Writable the next transmission data to the Transmit buffer register
at being set to “1.”
Transmit shift register shift completion flag
Check a completion of transmitting 1-byte data with this flag
“1” : Transmit shift completed
Serial I/O control register (Address : 1A16)
b7
b0
SIOCON 1 1 0 1
00
BRG counter source selection bit : f(XIN)
Serial I/O synchronous clock selection bit : BRG/4
Transmit enable bit : Transmit enabled
Receive enable bit : Receive disabled
Serial I/O mode selection bit : Clock synchronous serial I/O
Serial I/O enable bit : Serial I/O enabled
Baud rate generator (Address : 1C16)
b7
b0
BRG
7
Set “division ratio – 1”
Interrupt edge selection register (Address : 3A16)
b7
b0
INTEDGE
0
INT0 active edge selection bit : Select INT0 falling edge
Fig. 2.3.15 Setting of related registers at a transmitting side [Communication using a clock
synchronous serial I/O]
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3800 GROUP USER’S MANUAL