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12.4 Operation of Serial Interface UART6
Serial interface UART6 has the following two modes.
• Operation stop mode
• Asynchronous serial interface (UART) mode
12.4.1 Operation stop mode
In this mode, serial communication cannot be executed; therefore, the power consumption can be reduced. In
addition, the pins can be used as ordinary port pins in this mode. To set the operation stop mode, clear bits 7, 6, and
5 (POWER6, TXE6, and RXE6) of ASIM6 to 0.
(1) Register used
The operation stop mode is set by asynchronous serial interface operation mode register 6 (ASIM6).
ASIM6 can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets this register to 01H.
Address: FF50H After reset: 01H R/W
Symbol
<7>
ASIM6
POWER6
POWER6
Note 1
0
TXE6
0
RXE6
0
Notes 1.
The output of the T
POWER6 = 0.
2.
Asynchronous serial interface reception error status register 6 (ASIS6), asynchronous serial interface
transmission status register 6 (ASIF6), bit 7 (SBRF6) and bit 6 (SBRT6) of asynchronous serial
interface control register 6 (ASICL6), and receive buffer register 6 (RXB6) are reset.
Caution Clear POWER6 to 0 after clearing TXE6 and RXE6 to 0 to set the operation stop mode.
To start the operation, set POWER6 to 1, and then set TXE6 and RXE6 to 1.
Remark To use the RxD6/P14 and TxD6/P13 pins as general-purpose port pins, see CHAPTER 4 PORT
FUNCTIONS.
240
CHAPTER 12 SERIAL INTERFACE UART6
<6>
<5>
TXE6
RXE6
Enables/disables operation of internal operation clock
Disables operation of the internal operation clock (fixes the clock to low level) and asynchronously
Note 2
resets the internal circuit
.
Disables transmission operation (synchronously resets the transmission circuit).
Disables reception (synchronously resets the reception circuit).
D6 pin goes high and the input from the R
X
Preliminary User's Manual U16846EJ1V0UD
4
3
PS61
PS60
CL6
Enables/disables transmission
Enables/disables reception
X
2
1
SL6
ISRM6
D6 pin is fixed to high level when
0
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