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CHAPTER 14 SERIAL INTERFACE UART6
User’s Manual U19780EJ2V0UD
379
14.4 Operation of Serial Interface UART6
Serial interface UART6 has the following two modes.
•
Operation stop mode
•
Asynchronous serial interface (UART) mode
14.4.1 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 ( or 8-bit timer 50, 51
Not
) pins in this mode. To set the operation stop
mode, clear bits 7, 6, and 5 (POWER6, TXE6, and RXE6) of ASIM6 to 0.
Note
78K0/KB2-A only.
(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 signal generation sets this register to 01H.
Address: FF50H After reset: 01H R/W
Symbol
<7>
<6>
<5>
4 3 2 1 0
ASIM6 POWER6 TXE6
RXE6
PS61
PS60
CL6
SL6
ISRM6
POWER6
Enables/disables
operation of internal operation clock
0
Note 1
Disables operation of the internal operation clock (fixes the clock to low level) and asynchronously
resets the internal circuit
Note 2
.
TXE6
Enables/disables
transmission
0
Disables transmission operation (synchronously resets the transmission circuit).
RXE6
Enables/disables
reception
0
Disables
reception
(synchronously resets the reception circuit).
Notes 1.
If POWER6 = 0 is set while transmitting data, the output of the TxD6 pin will be fixed to high level (if
TXDLV6 = 0). Furthermore, the input from the RxD6 pin will be fixed to high level.
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 stop the operation.
To start the communication, set POWER6 to 1, and then set TXE6 or RXE6 to 1.
Remark
To use the R
X
D6/P11 and T
X
D6/P10 pins as general-purpose port pins, see
CHAPTER 4 PORT
FUNCTIONS
.