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Under
development
Preliminary Specifications REV.B3
Specifications in this manual are tentative and subject to change.
Mitsubishi Microcomputers
M32C/83 group
SINGLE-CHIP 16/32-BIT CMOS MICROCOMPUTER
UARTi Special Mode Register
187
UARTi Special Mode Register
UARTi (i=0 to 4) operate the IIC bus interface (simple IIC bus) using the UARTi special mode register
(addresses 036716, 02E716, 033716, 032716 and 02F716) and UARTi special mode register 2 (addresses
036616, 02E616, 033616, 032616 and 02F616). UARTi add special functions using UARTi special mode
resister 3 (addresses 036516, 02E516, 035516, 032516 and 02F516).
(1) IIC Bus Interface Mode
The I2C bus interface mode is provided with UARTi.
Table 1.21.1 shows the construction of the UARTi special mode register and UARTi special mode regis-
ter 2.
When the I2C mode select bit (bit 0 in addresses 036716, 02E716, 033716, 032716 and 02F716) is set to
“1”, the I2C bus (simple I2C bus) interface circuit is enabled.
To use the I2C bus, set the SCLi and the SDAi of both master and slave to output with the function select
register. Also, set the data output select bit (bit 5 in address 036C16, 02EC16, 033C16, 032C16 and
02FC16) to N-channel open drain output.
Table 1.21.1 shows the relationship of the IIC mode select bit to control. To use the chip in the clock
synchronized serial I/O mode or UART mode, always set this bit to “0”.
Function
Normal mode (IICM=0)
I2C mode (IICM=1)
Factor of interrupt number 17, 19, 33, 35, 37
UARTi transmission
No acknowledgment detection (NACK)
Factor of interrupt number 18, 20, 34, 36, 38
UARTi reception
Start condition detection or stop
condition detection
UARTi transmission output delay
Not delayed
Delayed
P63, P67, P70, P92, P96 at the time when UARTi
is in use
TxDi (output)
SDAi (input/output)
P62, P66, P71, P91, P97 at the time when UARTi
is in use
RxDi (input)
SCLi (input/output)
P61, P65, P72, P90, P95 at the time when UARTi
is in use
CLKi
P61, P65, P72, P90, P95
DMA factor at the time
UARTi reception
Acknowledgment detection (ACK)
Noise filter width
15ns
50ns
Reading P62, P66, P71, P91, P97
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 I2C mode is used.
Set 0 1 0 in bits 2, 1, 0 of the UARTi transmission/reception mode register.
Disable the RTS/CTS function. Choose the MSB First function.
Note 2: Follow the steps given below to switch from one 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 IIC mode (IIC mode select bit = "1") is valid and serial I/O is invalid.
Factor of interrupt number 39 to 41
Bus collision detection
Acknowledgment detection (ACK)
10
Initial value of UARTi output
H level (when 0 is assigned to
the CLK polarity select bit)
The value set in latch P63, P67, P70,
P92, P96 when the port is selected
11
(Note 2)
(Note 1)
(Note 3)
Table 1.21.1. Features in I2C mode