M16C Datasheet, PDF (138/262 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Preliminary Specifications REV.B
Specifications in this manual are tentative and subject to change.
Mitsubishi microcomputers
M16C / 6N Group
CUlAoRckTa2sSynpcehcriaolnMouosdeseRrieagl Iis/Oter(UART) mode
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
UART2 Special Mode Register
The UART2 special mode register (address 01F716) is used to control UART2 in various ways.
Figure 13-11 shows the special UART2 mode register.
UART2 special mode register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
U2SMR
Address
01F716
When reset
X00000002
Bit
symbol
Bit name
Function
(During clock synchronous
serial I/O mode)
Function
(During UART mode)
RW
IICM I²C mode selection bit 0 : Normal mode
1 : I²C mode
Must always be “0”
ABC
BBS
LSYN
Arbitration loss detecting 0 : Update per bit
flag control bit
1 : Update per byte
Must always be “0”
Bus busy flag
0 : STOP condition detected Must always be “0”
1 : START condition detected
SCLL sync output
enable bit
0 : Disabled
1 : Enabled
Must always be “0”
(Note)
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
Nothing is assigned.
This bit can neither be set nor reset. When read, its content is indeterminate.
Note: Nothing but "0" may be written.
Figure 13-11. UART2 special mode register
Table13-5. Features in I²C mode
Function
1 Factor of interrupt number 10 (Note 2)
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
Normal mode
Bus collision detection
UART2 transmission
UART2 reception
Not delayed
TxD2 (output)
RxD2 (input)
CLK2
UART2 reception
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)
9 Noise filter width
10 Reading P71
15ns
Reading the terminal when 0 is
assigned to the direction register
50ns
Reading the terminal regardless of the
value of the direction register
11 Initial value of UART2 output
H level (when 0 is assigned to
the CLK polarity select bit)
The value set in latch P70 when the port is
selected
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. Select TXD2 as Nch. Choose the LSB 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.
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