
1-108
Under
development
Specifications in this manual are tentative and subject to change
Rev. H
Serial Communications
MITSUBISHI MICROCOMPUTERS
M30222 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Fig. 1.81. Serial I/O related register (1)
b7
UARTi bit rate generator
b0
Symbol
Address
When reset
U0BRG
03A116
Indeterminate
U1BRG
03A916
Indeterminate
U2BRG
037916
Indeterminate
Function
Assuming that set value = n, BRGi divides the count source by
n + 1
0016 to FF16
Values that can be set
W
R
b7
b0
(b15)
(b8)
b7
b0
UARTi transmit buffer register
Function
Transmit data
Nothing is assigned.
In an attempt to write to these bits, write “0”. The value, if read, turn out to be indeterminate.
Symbol
Address
When reset
U0TB
03A316, 03A216
Indeterminate
U1TB
03AB16, 03AA16
Indeterminate
U2TB
037B16, 037A16
Indeterminate
W
R
(b15)
Symbol
Address
When reset
U0RB
03A716, 03A616
Indeterminate
U1RB
03AF16, 03AE16
Indeterminate
U2RB
037F16, 037E16
Indeterminate
b7
b0
(b8)
b7
b0
UARTi receive buffer register
Function
(During UART mode)
Function
(During clock synchronous
serial I/O mode)
Bit name
Bit
symbol
Note 1: Bits 15 through 12 are set to “0” when the serial I/O mode select bit (bits 2 to 0 at addresses 03A0 16
03A816 and 037816) are set to “0002” or the receive enable bit is set to “0”.
(Bit 15 is set to “0” when bits 14 to 12 all are set to “0”.) Bits 14 and 13 are also set to “0” when the
lower byte of the UARTi receive buffer register (addresses 03A6 16, 03AE16 and 037E16) is read out.
Note 2: Arbitration lost detecting flag is allocated to U2RB and only “0” may be written. Nothing is
assigned in bit 11 of U0RB and U1RB. These bits can neither be set or reset. When read, the value
of this bit is “0”.
Receive data
W
R
Receive data
0 : No framing error
1 : Framing error found
0 : No parity error
1 : Parity error found
0 : No error
1 : Error found
Invalid
OER
FER
PER
SUM
Overrun error flag (Note 1)
Framing error flag (Note 1)
Parity error flag (Note 1)
Error sum flag (Note 1)
0 : No overrun error
1 : Overrun error found
0 : No overrun error
1 : Overrun error found
ABT
Arbitration lost detecting
flag (Note 2)
0 : Not detected
1 : Detected
O
Nothing is assigned.
Invalid
O O
Invalid
Note 3: Mode fault flag is allocated to U2RB only. Nothing is assigned in bit 10 of U0RB and U1RB.
The bit is read only. After MDFLT is set, it can be reset only by exiting SPI mdoe.
MDFLT
SPI Mode fault flag
(Note 3)
0 : Not detected
1 : Detected
Write "0" when writing to this bit. If read, the value is "0".