M16C62 Datasheet, PDF (115/231 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

UART2 Special Mode Register
Mitsubishi microcomputers
M16C / 62 Group (80-pin)
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
UART2 Special Mode Register
The UART2 special mode register (address 037716) is used to control UART2 in various ways.
Figure 1.14.26 shows the UART2 special mode register.
UART2 special mode register
b7 b6 b5 b4 b3 b2 b1 b0
0
Symbol
U2SMR
Address
037716
When reset
0016
Bit
symbol
Bit name
IICM
I²C mode selection bit
Function
(During clock synchronous
serial I/O mode)
0 : Normal mode
1 : I²C mode
Function
(During UART mode)
Must always be “0”
RW
ABC
BBS
LSYN
Arbitration lost detecting
flag control bit
Bus busy flag
0 : Update per bit
1 : Update per byte
0 : STOP condition detected
1 : START condition detected
Must always be “0”
Must always be “0”
SCLL sync output
enable bit
0 : Disabled
1 : Enabled
Must always be “0”
(Note1)
ABSCS ^{Bus collision detect}
Must always be “0”
sampling clock select bit
ACSE
SSS
Auto clear function
select bit of transmit
enable bit
Transmit start condition
select bit
Must always be “0”
Must always be “0”
0 : Rising edge of transfer
clock
1 : Underflow signal of timer A0
0 : No auto clear function
1 : Auto clear at occurrence of
bus collision
0 : Ordinary
1 : Falling edge of RxD2
Reserved bit
Always set to “0”
Note 1: Nothing but “0” may be written.
Note 2: UART2 clock synchronous serial I/O mode cannot be used in M16C/62 (80-pin version) group.
Figure 1.14.26. UART2 special mode register
Table 1.14.8. Features in I²C mode
Function
Normal mode
1 Factor of interrupt number 10 (Note 2)
Bus collision detection
2 Factor of interrupt number 15 (Note 2)
3 Factor of interrupt number 16 (Note 2)
4 UART2 transmission output delay
5 P70 at the time when UART2 is in use
6 P71 at the time when UART2 is in use
7 P72 at the time when UART2 is in use
8
DMA1 factor at the time when 1 1 0 1 is assigned
to the DMA request factor selection bits
UART2 transmission
UART2 reception
Not delayed
TxD2 (output)
RxD2 (input)
CLK2
UART2 reception
9 Noise filter width
10 Reading P71
15ns
Reading the terminal when 0 is
assigned to the direction register
11 Initial value of UART2 output
H level (when 0 is assigned to
the CLK polarity select bit)
Note 1: Make the settings given below when I²C mode is in use.
Set 0 1 0 in bits 2, 1, 0 of the UART2 transmission/reception mode register.
Disable the RTS/CTS function. Choose the MSB First function.
Note 2: Follow the steps given below to switch from a factor to another.
1. Disable the interrupt of the corresponding number.
2. Switch from a factor to another.
3. Reset the interrupt request flag of the corresponding number.
4. Set an interrupt level of the corresponding number.
Note 3: Set an initial value of SDA transmission output when serial I/O is invalid.
I²C mode (Note 1)
Start condition detection or stop
condition detection
No acknowledgment detection (NACK)
Acknowledgment detection (ACK)
Delayed
SDA (input/output) (Note 3)
SCL (input/output)
P72
Acknowledgment detection (ACK)
50ns
Reading the terminal regardless of the
value of the direction register
The value set in latch P70 when the port is
selected
114