
1-135
Under
development
Specifications in this manual are tentative and subject to change
Rev. H
UART2 in I2C Mode
MITSUBISHI MICROCOMPUTERS
M30222 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Table 1.43. Functions changed by I2C mode select bit 2
UART2 Special Mode Register 2
UART2 special mode register 2 (address 037616) is used to further control UART2 in I2C mode. Figure
1.107 shows the UART2 special mode register 2.
Bit 0 of the UART2 special mode register 2 (address 037616) is used as the I2C mode select bit 2.
Table 1.43 shows the types of control to be changed by I2C mode select bit 2 when the I2C mode
select bit is set to “1”. Figure 1.108 shows the timing characteristics of detecting the start condition
and the stop condition. Set the start/stop condition control bit (bit 7 of UART2 special mode register 2)
to “1” in I2C mode.
Fig. 1.107. UART2 special mode register 2
Function
IICM2 = 1
IICM2 = 0
Factor of interrupt number 15
No acknowledgment detection (NACK)
UART2 transmission (the rising edge
of the final bit of the clock)
Factor of interrupt number 16
Acknowledgment detection (ACK)
UART2 reception (the falling edge
of the final bit of the clock)
DMA1 factor at the time when 1 1 0 1
is assigned to the DMA request
factor selection bits
Acknowledgment detection (ACK)
UART2 reception (the falling edge of
the final bit of the clock)
Timing for transferring data from the
UART2 reception shift register to the
reception buffer.
The rising edge of the final bit of the
reception clock
The falling edge of the final bit of the
reception clock
Timing for generating a UART2
reception/ACK interrupt request
The rising edge of the final bit of the
reception clock
The falling edge of the final bit of the
reception clock
1
2
3
4
5
UART2 special mode register 2
Symbol
Address
When reset
U2SMR2
037616
0016
b7 b6 b5 b4 b3 b2 b1 b0
Bit name
Bit
symbol
W
R
Function
STAC
SWC2
SDHI
I C mode selection bit 2
SCL wait output bit
0 : Disabled
1 : Enabled
SDA output stop bit
UART2 initialization bit
Clock-synchronous bit
Refer to Table 1.43
0 : Disabled
1 : Enabled
IICM2
CSC
SWC
ASL
0 : Disabled
1 : Enabled
SDA output disable bit
SCL wait output bit 2
0: Enabled
1: Disabled (high impedance)
0 : Disabled
1 : Enabled
0: UART2 clock
1: 0 output
(Note)
2
SHTC
Start/stop condition
control bit
Set this bit to "1" in I 2C mode
(refer to Figure 1.108)