Datasheet

CHAPTER 14 SERIAL INTERFACE UART6
User’s Manual U18698EJ1V0UD
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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 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: 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. The output of the T
XD6 pin goes high and the input from the RXD6 pin is fixed to high level when
POWER6 = 0 during 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 stop the operation.
To start the communication, set POWER6 to 1, and then set TXE6 or RXE6 to 1.
Remark To use the R
XD6/P12 and TXD6/P13 or RXD6/P113 and TXD6/P112 pins as general-purpose port pins,
see CHAPTER 4 PORT FUNCTIONS.