Preliminary User’s Manual U16315EJ1V0UD
245
CHAPTER 13 SERIAL INTERFACE UART0
13.1 Functions of Serial Interface UART0
Serial interface UART0 has the following two modes.
(1) Operation stop mode
This mode is used when serial transfer is not executed and can enable a reduction in the power consumption.
For details, refer to
13.4.1 Operation stop mode
.
(2) Asynchronous serial interface (UART) mode
The functions of this mode are outlined below.
•
Two-pin configuration
T
X
D0: Transmit data output pin
R
X
B0: Receive data input pin
•
Length of transfer data can be selected from 7 or 8 bits.
•
Dedicated on-chip 5-bit baud rate generator allowing any baud rate to be set
•
Transmission and reception can be performed independently.
•
Four operating clock inputs selectable
•
Fixed to LSB-first transfer
Cautions 1. The initial value of the T
X
D0 pin is high level. Exercise care when using the T
X
D0 pin as a
port pin.
2. If clock supply to serial interface UART0 is not stopped (e.g., in the HALT mode), normal
operation continues. If clock supply to serial interface UART0 is stopped (e.g., in the STOP
mode), each register stops operating, and holds the value immediately before clock supply
was stopped. The T
X
D0 pin also holds the value immediately before clock supply was
stopped and outputs it. However, the operation is not guaranteed after clock supply is
resumed. Therefore, reset the circuit so that POWER0 = 0, RXE0 = 0, and TXE0 = 0.
3. Set POWER0 = 1 and then set TXE0 = 1 (transmission) or RXE0 = 1 (reception) to start
communication.
4. TXE0 and RXE0 are synchronized with the base clock (f
XCLK
) set by BRGC0. Therefore, the
transmission unit may not be initialized if TXE0 = 1 is not set again 2 clocks after TXE0 = 0
is set. Similarly, the reception unit may not be initialized if RXE0 = 1 is not set again 2
clocks after RXE0 = 0 is set.
Содержание 78K0/KD1 Series
Страница 2: ...Preliminary User s Manual U16315EJ1V0UD 2 MEMO ...
Страница 444: ...Preliminary User s Manual U16315EJ1V0UD 444 MEMO ...