21

µPD780921, 780922, 780923, 780924

5.6 SERIAL INTERFACE

Two independent serial interface channels (UART00 and UART01) are incorporated.

Each serial interface incorporates a baud-rate generator. Therefore, it is possible to set a serial transfer rate that is

independent of the operating clock frequency.

The serial transfer rate can be set from 75 to 76800 bps (@ fx = 8.38-MHz operation) by setting the mode register.

Table 5-7. Serial Interface Block Diagram

Remark n = 0, 1

Internal Bus

Receive

Buffer

RXBn

RxD0n

TxD0n

Receive

Shift

Register

Transmit

Shift

Register

PE0n FE0n OVE0n

ASIS0n

TXSn

Receive

Control

Parity

Check

Transmit

Control

Parity

Add

INTSERn

INTSTn

Baud Rate

Generator

fX/2 to fX/28

(when UART00)

TXE0n RXE0n PS0n1 PS0n0 CL0n SL0n ISRM0n IRDAM0n

ASIM0n

INTSRn

fX/24 to fX/211

(when UART01)