UPD784044 Datasheet, PDF (37/90 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLER

µPD784044(A), 784046(A)
7.6.1 Asynchronous serial interface/3-wire serial I/O (UART/IOE)
Two serial interface channels from which asynchronous serial interface mode and three-wire serial I/O mode
can be selected are provided.
(1) Asynchronous serial interface mode
In this mode, 1-byte data following a start bit is transferred or received.
The internal baud rate generator allows communication in a wide range of baud rates.
The clock input to the ASCK pin can also be divided to define a baud rate.
The baud rate generator can also set a baud rate conforming to the MIDI standard (31.25 kbps).
Figure 7-8. Block Diagram in Asynchronous Serial Interface Mode
Internal bus
Receive buffer RXB, RXB2
RxD, RxD2
TxD, TxD2
Baud rate generator
fCLK
ASCK, ASCK2
Receive shift
register
Transmit shift
register
TXS, TXS2
Receive control
Parity check
INTSR,
INTSR2
INTSER,
INTSER2
Transmit control
Parity append
INTST, INTST2
1/2ⁿ⁺¹
1/2m
1/2m
Remark fCLK: internal system clock
n = 0 to 11
m = 16 to 30
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