Serial I/O
115
Mitsubishi microcomputers
M16C / 62N Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Figure 1.17.4. Serial I/O-related registers (1)
b7
UARTi bit rate generator (Note 1, 2)
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 (Note)
Function
Transmit data
Nothing is assigned.
In an attempt to write to these bits, write “0”. The value, if read, turns 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
0 : No framing error
1 : Framing error found
0 : No parity error
1 : Parity error found
0 : No error
1 : Error found
Note 1: Bits 15 through 12 are set to “0” when the serial I/O mode select bit (bits 2 to 0 at addresses 03A016,
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 03A616, 03AE16 and 037E16) is read out.
Note 2: Arbitration lost detecting flag is allocated to U2RB and noting but “0” may be written. Nothing is
assigned in bit 11 of U0RB and U1RB. When write, set “0”. The value, if read, turns out to be “0”.
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
Nothing is assigned.
In an attempt to write to these bits, write “0”. The value, if read, turns out to be “0”.
Receive data
W
R
Receive data
ABT
Arbitration lost detecting
flag (Note 2)
Invalid
0 : Not detected
1 : Detected
Note 1: Write a value to this register while transmit/receive halts.
Note 2: Use MOV instruction to write to this register.
Note: Use MOV instruction to write to this register.