MITSUBISHI MICROCOMPUTERS
7477/7478 GROUP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
b7
b0
b7
b0
Serial I/O status register
(SIOSTS: address 00E116
Serial I/O control register
(SIOCON: address 00E216
)
)
BRG count source selection bit (CSS)
0 : f(XIN)divided by 4
1 : f(XIN)divided by16
Transmit buffer empty flag (TBE)
0 : Buffer full
1 : Buffer empty
Serial I/O synchronous clock selection bit (SCS)
0 : BRG output divided by 4 (when clock synchronous
serial I/O is selected)
Receive buffer full flag (RBF)
0 : Buffer empty
1 : Buffer full
BRG output divided by 16 (when UART is selected)
1 : External clock input (when clock synchronous
serial I/O is selected )
Transmit shift completion flag (TSC)
0 : Transmit shift in progress
1 : Transmit shift completed
Overrun error flag (OE)
0 : No error
1 : Overrun error
Parity error flag (PE)
0 : No error
1 : Parity error
External clock input divided by16 (when UART is selected
)
S
RDY output enable bit (SRDY)
0 : P1
7
7
pin operates as ordinary I/O pin
pin operates as SRDY output pin
1 : P1
Transmit interrupt source selection bit (TIC)
0 : Interrupt when transmit buffer has emptied.
1 : Interrupt when transmit shift operation is completed.
Transmit enable bit (TE)
0 : Transmit disabled
1 : Transmit enabled
Framing error flag (FE)
0 : No error
1 : Framing error
Summing error flag (SE)
0 : (OE)U(PE)U(FE)=0
1 : (OE)U(PE)U(FE)=1
Receive enable bit (RE)
0 : Receive disabled
1 : Receive enabled
Not used (returns “1” when read)
Serial I/O mode selection bit (SIOM)
0 : Asynchronous serial I/O (UART)
1 : Clock synchronous serial I/O
Serial I/O enable bit (SIOE)
0 : Serial I/O disabled
b7
b0
(pins P1
I/O pins)
1 : Serial I/O enabled
(pins P1
to P1 operate as serial
I/O pins)
4 to P17 operate as ordinary
UART control register
(UARTCON: address 00E316
)
Character length selection bit (CHAS)
0 : 8 bits
1 : 7 bits
4
7
Parity enable bit (PARE)
0 : Parity checking disabled
1 : Parity checking enabled
Parity selection bit (PARS)
0 : Even parity
1 : Odd parity
Stop bit length selection bit (STPS)
0 : 1 stop bit
1 : 2 stop bits
Not used (returns “1” when read)
Fig. 12 Structure of serial I/O control registers
20
MITSUBISHI [ Mitsubishi Group ]
