m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 289

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

SERIAL I/O
11.3 Clock synchronous serial I/O mode
11-34
Fig. 11.3.11 Receive operation
Fig. 11.3.12 Example of receive timing (when external clock selected)
Receive complete flag
interrupt request bit
Transmit enable bit
Receive enable bit
Transfer clock output from
or input to CLKi pin (Note).
Transmit buffer
UARTi receive
empty flag
The above timing diagram applies when the following
conditions are satisfied:
f
EXT
External clock selected
RTS function selected
CLK polarity select bit = “0”
: Frequency of external clock
RTS
CLK
RxD
Note: This applies when the CLK polarity select bit = “0.”
i
i
i
When the CLK polarity select bit = “1,” data is shifted at the rising edge of
the transfer clock.
UARTi receive register UARTi receive buffer register
•
• •
UARTi receive buffer register
D
0
D
7905 Group User’s Manual Rev.1.0
1
UARTi receive register
Dummy data is set to UARTi transmit buffer register.
D
2
D
3
D
4
1/f
Receive data is taken in.
D
EXT
5
D
6
D
Cleared to “0” when interrupt request is accepted or
cleared to “0” by software.
7
MSB
b7
When the CLK
the following conditions:
D
D
D
D
1
2
7
0
Writing of dummy data to UARTi transmit buffer re
Transmit enable bit = “1”
Receive enable bit = “1”
UARTi transmit register UARTi transmit buffer
D
D
D
D
0
1
6
0
D
D
D
1
Receive data
0
5
UARTi receive buffer register is read o
i
D
pin’s input level is “H,” be sure to sati
D
2
4
D
•
•
•
3
D
3
D
4
D
2
D
5
D
1
LSB
D
b0
0