
1-108
Under
Specifications in this manual are tentative and subject to change
Rev. G
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
U0BRG
U1BRG
U2BRG
Address
03A1
16
03A9
16
0379
16
When reset
Indeterminate
Indeterminate
Indeterminate
Function
Assuming that set value = n, BRGi divides the count source by
n + 1
00
16
to FF
16
Values that can be set
W
R
b0
(b7
(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
U0TB
U1TB
U2TB
Address
03A3
16
, 03A2
16
03AB
16
, 03AA
16
037B
16
, 037A
16
When reset
Indeterminate
Indeterminate
Indeterminate
W
R
(b15)
b7
Symbol
U0RB
U1RB
U2RB
Address
03A7
16
, 03A6
16
03AF
16
, 03AE
16
037F
16
, 037E
16
When reset
Indeterminate
Indeterminate
Indeterminate
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
03A8
16
and 0378
16
) are set to
“
000
2
”
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
, 03AE
16
and 037E
16
) 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
”
.
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.
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
Invalid
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.
Write "0" when writing to this bit. If read, the value is "0".
Invalid
O O
Invalid
MDFLT
SPI Mode fault flag
(Note 3)
0 : Not detected
1 : Detected