CHAPTER 11 SERIAL INTERFACE UART6
User’s Manual U16898EJ3V0UD
192
11.4 Operation of Serial Interface UART6
Serial interface UART6 has the following two modes.
•
Operation stop mode
•
Asynchronous serial interface (UART) mode
11.4.1 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 signal generation sets this register to 01H.
Address: FF90H After reset: 01H R/W
Symbol
<7>
<6>
<5>
4 3 2 1 0
ASIM6 POWER6 TXE6 RXE6 PS61
PS60
CL6
SL6
ISRM6
POWER6
Enabling/disabling
operation of internal operation clock
0
Note 1
Disable operation of the internal operation clock (fix the clock to low level) and asynchronously
reset the internal circuit
Note 2
.
TXE6
Enabling/disabling
transmission
0
Disable transmission operation (synchronously reset the transmission circuit).
RXE6
Enabling/disabling
reception
0
Disable reception (synchronously reset the reception circuit).
Notes 1.
The output of the T
X
D6 pin goes high and the input from the R
X
D6 pin is fixed to high level when
POWER6 = 0 during a transmission.
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/P44 and TxD6/INTP1/P43 pins as general-purpose port pins, see
CHAPTER 4 PORT
FUNCTIONS
.