M306H2MC-XXXFP Datasheet, PDF (121/210 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

MITSUBISHI MICROCOMPUTERS
M306H2MC-XXXFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
with DATA ACQUISITION CONTROLLER
2.11.5 UART2 Special Mode Register
The UART2 special mode register (address 037716) is used to control UART2 in various ways.
Figure 2.11.26 shows the UART2 special mode register.
Bit 0 of the UART special mode register (037716) is used as the I²C mode selection bit.
Setting “1” in the I²C mode select bit (bit 0) goes the circuit to achieve the I²C bus interface effective.
Since this function uses clock-synchronous serial I/O mode, set this bit to “0” in UART mode.
UART2 special mode register
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
U2SMR
Address
037716
When reset
0016
Bit
symbol
Bit name
IICM
I²C mode selection bit
ABC
BBS
Arbitration lost detecting
flag control bit
Bus busy flag
LSYN
SCLL sync output
enable bit
ABSCS ^{Bus collision detect}
sampling clock select bit
ACSE
SSS
Auto clear function
select bit of transmit
enable bit
Transmit start condition
select bit
Function
(During clock synchronous
serial I/O mode)
0 : Normal mode
1 : I ²C mode
Function
(During UART mode)
Must always be “0”
RW
0 : Update per bit
1 : Update per byte
0 : STOP condition detected
1 : START condition detected
0 : Disabled
1 : Enabled
Must always be “0”
Must always be “0”
Must always be “0”
(Note 1)
Must always be “0”
0 : Rising edge of transfer
clock
1 : Underflow signal of timer A0
Must always be “0”
Must always be “0”
0 : No auto clear function
1 : Auto clear at occurrence of
bus collision
0 : Ordinary
1 : Falling edge of RxD2
SDDS
SDA digital delay select
bit
(Notes 2 and 3)
0 : Selects analog delay
output
1 : Selects digital delay
output (Must always
be “0” except at I ²C
mode)
Must always be “0”
Notes 1: Nothing but "0" may be written.
2: Do not write "1" except at I ²C mode. Must always be “0” at normal mode.
Bit 7 to bit5 (DL2 to DL0 = SDA digital delay value setting bit) of UART2 special mode
register 3 (U2SMR3/address 0375 16) are initialized and become “000” when this bit is "0", analog
delay circuit is selected. Reading and writing U2SMR are enable when SDDS = "0" .
3: Delaying ; Only analog delay value when analog delay is selected, and only digital delay value
when digital delay is selected.
UART2 special mode register 3 (I²C bus exclusive register)
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
U2SMR3
Address
037516
When reset
Indeterminate
(initializing value is "00 16" at SDDS = "1")
Bit
symbol
Bit name
Function
(I²C bus exclusive)
Nothing is assigned.
In an attempt to write to this bit, write “0”. The value, if read, turns out to be “0”.
“0” is read out when SDDS = 1.
DL0
SDA digital delay value ^{b7 b6 b5}
set bit
0 0 0 : Selects analog delay
0 0 1 : 1–2 cycle of 1/f (Xin)(Digital delay)
DL1
0 1 0 : 2–3 cycle of 1/f (Xin)(Digital delay)
0 1 1 : 3–4 cycle of 1/f (Xin)(Digital delay)
1 0 0 : 4–5 cycle of 1/f (Xin)(Digital delay)
DL2
1 0 1 : 5–6 cycle of 1/f (Xin)(Digital delay)
1 1 0 : 6–7 cycle of 1/f (Xin)(Digital delay)
1 1 1 : 7–8 cycle of 1/f (Xin)(Digital delay)
Notes 1: Reading and writing is possible when bit7 (SDDS = SDA digital delay selection
bit) of UART2 special mode register (U2SMR/address 0377 16) is "1". When
set SDDS = "1" and read out initialized value of UART2 special mode register
3(U2SMR3), this value is "00 16".When set SDDS = "1" and write to UART2
special mode register 3(U2SMR3), set "0" to bit 0 to bit 4. When SDDS = "0",
writing is enable. When read out, this value is indeterminate.
2: When SDDS = "0" , this bit is initialized and become "000", selected analog
delay circuit. This bit is become "000" after end reset released, and selected
analog delay circuit. Reading out is possible when only SDDS = "1". when
SDDS = "0", value which was read out is indeterminate.
3: Delaying ; Only analog delay value when analog delay is selected, and only
digital delay value when digital delay is selected.
4: Delay level depends on SCL pin and SDA pin. And, when use external clock,
delay is increase around 100ns. So test first, and use this.
RW
Figure 2.11.26 UART2 special mode register
120
Rev. 1.0