UPD78F9234MC-5A4-A Datasheet, PDF (200/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 11 SERIAL INTERFACE UART6
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
ASIM6
POWER6
TXE6
RXE6
PS61
PS60
CL6
1
0
SL6
ISRM6
POWER6
0^{Note 1}
Enabling/disabling operation of internal operation clock
Disable operation of the internal operation clock (fix the clock to low level) and asynchronously
reset the internal circuit^{Note 2}.
TXE6
0
Enabling/disabling transmission
Disable transmission operation (synchronously reset the transmission circuit).
RXE6
0
Enabling/disabling reception
Disable reception (synchronously reset the reception circuit).
Notes 1.
2.
The output of the TXD6 pin goes high and the input from the RXD6 pin is fixed to high level when
POWER6 = 0 during a transmission.
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.
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User’s Manual U17446EJ5V0UD