165
CHAPTER 14 SERIAL INTERFACE UART
14.1 UART Functions
The serial interface UART has the following two modes.
(1) Operation stop mode
This mode is used when serial transfers are not performed to reduce power consumption.
For details, see 14.4.1 Operation stop mode.
(2) Asynchronous serial interface (UART) mode
This mode enables full-duplex operation wherein one byte of data is transmitted and received after the start bit.
The on-chip dedicated UART baud rate generator enables communications using a wide range of selectable baud
rates.
The UART baud rate generator can also be used to generate a MIDI-standard baud rate (31.25 kbps).
For details, see 14.4.2 Asynchronous serial interface (UART) mode.
Figure 14-1 shows the UART block diagram.
Figure 14-1. UART Block Diagram
Internal bus
Internal bus
Receive buffer
register (RXB)
Receive shift
register (RXS)
Direction control
circuit
Direction control circuit
Transmit control circuit
Baud rate generator
Transmit shift
register (TXS)
Receive control
circuit
3
3
4
Asynchronous serial interface
status register (ASIS)
Asynchronous serial interface mode register (ASIM)
Baud rate generator control register (BRGC)
RxD/P53
TxD/P54
INTSER
INTSR
TXE
INTST
TXE RXE PS1 PS0 CL
SL ISRM
TPS2 TPS1 TPS0 MDL3 MDL2 MDL1 MDL0
FE
PE
OVE
f
X
/2
f
X
/2
2
f
X
/2
3
f
X
/2
4
f
X
/2
5
f
X
/2
6
f
X
/2
7
f
X
/2
8
Selector
f
SCK
Содержание mPD780973 Series
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