M16C26 Datasheet, PDF (147/239 Pages) Renesas Technology Corp – 16-BIT CMOS SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/20 SERIES

Udenvdeelropment
Preliminary Specifications Rev.
Specifications in this manual are
UART2 Special Mode Register
0.9
tentative
and
subject to change.
SINGLE-CHIP 16-BIT
M16C/26 Group
CMOS MICROCOMPUTER
UART2 Special Mode Register
The UART2 special mode register (address 037716) is used to control UART2 in various ways.
Bit 0 of the UART2 special mode register are used as the I²C mode select bit.
Setting “1” in the I²C mode select bit (bit 0) goes the circuit to achieve the I²C bus (simplified I²C bus)
interface effective.
Table 1.15.13 shows the relation between the I²C mode select bit and respective control workings.
Since this function uses clock-synchronous serial I/O mode, set this bit to “0” in UART mode.
Table 1.15.13. Features in I²C mode
Function
Normal mode
1 Factor of interrupt number 10 (Note 2, 4)
Bus collision detection
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 1101 is assigned to
the DMA request factor selection bits
UART2 transmission
UART2 reception
Not delayed
TxD2 (output)
RxD2 (input)
CLK2
UART2 reception
9 Noise filter width
10 Reading P71
11 Initial value of UART2 output
15ns
Reading the terminal when 0 is
assigned to the direction register
H level (when 0 is assigned to
the CLK polarity select bit)
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. 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.
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)
200ns
Reading the terminal regardless of the
value of the direction register
The value set in latch P70 when the
port is selected (Note 3)
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