![](http://datasheet.mmic.net.cn/90000/M306H2MC-XXXFP_datasheet_3496122/M306H2MC-XXXFP_124.png)
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
with DATA ACQUISITION CONTROLLER
MITSUBISHI MICROCOMPUTERS
121
Rev. 1.0
M306H2MC-XXXFP
Figure 2.11.27 Functional block diagram for I2C mode
Function
Normal mode
I2C mode (Note 1)
Factor of interrupt number 15 (Note 2)
UART2 transmission
No acknowledgment detection (NACK)
Factor of interrupt number 16 (Note 2)
UART2 reception
Start condition detection or stop
condition detection
UART2 transmission output delay
Not delayed
Delayed(Digital / analog selection is possible)
P70 at the time when UART2 is in use
TxD2 (output)
SDA (input/output) (Note 3)
P71 at the time when UART2 is in use
RxD2 (input)
SCL (input/output)
P72 at the time when UART2 is in use
CLK2
P72
DMA1 factor at the time when 1 1 0 1 is assigned
to the DMA request factor selection bits
UART2 reception
Acknowledgment detection (ACK)
Noise filter width
15ns
50ns
Reading P71
Reading the terminal when 0 is
assigned to the direction register
Reading the terminal regardless of the
value of the direction register
1
2
3
4
5
6
7
8
9
Note 1: Make the settings given below when I 2C 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.
Factor of interrupt number 10 (Note 2)
Bus collision detection
Acknowledgment detection (ACK)
10
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
11
Table 2.11.9 Features in I2C mode
IICM=1
and IICM2=0
IICM=0
or IICM2=1
To DMA0
I/O
Noize
Filter
P71/RXD2/SCL
Reception register
CLK
control
UART2
Noize
Filter
UART2
P72/CLK2
D
T
Q
D
T
Q
UART2
R
IICM=1
IICM=0
IICM=1
IICM=0
S
R
Q
SWC
Falling of 9th pulse
SWC2
Start condition detection
Stop condition detection
Falling edge
detection
L-synchronous
output enabling bit
Data bus
Selector
Internal clock
External clock
Selector
I/O
Timer
Port reading
Bus
busy
UART2 reception/ACK interrupt request
DMA1 request
NACK
ACK
IICM=1
IICM=0
*
With IICM set to 1, the port terminal is to be readable
even if 1 is assigned to P71 of the direction register.
Bus collision
detection
9th pulse
Bus collision/start, stop condition detection
interrupt request
Noize
Filter
D
T
Q
IICM=1
and IICM2=0
IICM=0
or IICM2=1
To DMA0, DMA1
UART2 transmission/
NACK interrupt request
I/O
UART2
P70/TXD2/SDA
Selector
Timer
Transmission
register
Arbitration
Analog
delay
UART2
IICM=1(SDDS=0)
or DL=000(SDDS=1)
ALS
SDHI
IICM=0
or DL=000(SDDS=1)
SDDS=1
and DL=000
Digital Delay
(Divier)
SDDS=0
or DL=000
Q
(Port P71 output data latch)
P70 through P72 conforming to the simplified I2C bus