Operation In Asynchronous Mode; Serial Data Transfer Format - Renesas RZ/A Series User Manual

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RZ/A1L Group, RZ/A1LU Group, RZ/A1LC Group

Operation in Asynchronous Mode

Figure 15.2 shows the general format for asynchronous serial communications.

One frame consists of a start bit (low level), transmit/receive data, a parity bit, and stop bits (high level).

In asynchronous serial communications, the communications line is usually held in the mark state (high level).

The SCI monitors the communications line, and when it goes to the space state (low level), recognizes a start bit and

starts serial communications.

Inside the SCI, the transmitter and receiver are independent units, enabling full-duplex communications. Both the

transmitter and the receiver also have a double-buffered structure, so that data can be read or written during transmission

or reception, enabling continuous data transmission and reception.

Data Format in Asynchronous Serial Communications

(Example with 8-Bit Data, Parity, Two Stop Bits)

Table 15.14 lists the serial data transfer formats that can be used in asynchronous mode.

Any of 12 transfer formats can be selected according to the SMR setting. For details of multi-processor function, see

section 15.4, Multi-Processor Communications Function.

R01UH0437EJ0600 Rev.6.00

Jan 29, 2021

Transmit/receive data

One unit of transfer data (character or frame)

15. Serial Communications Interface

(mark state)

Rz/a1 series Rz/a1lu series Rz/a1lc series