HD6433636SW datasheet(284/418 Pages) RENESAS

284 / 418 page

270

Break Detection and Processing: Break signals can be detected by reading the RXD pin directly

when a framing error (FER) is detected. In the break state the input from the RXD pin consists of

all 0s, so FER is set and the parity error flag (PER) may also be set. In the break state SCI3

continues to receive, so if the FER bit is cleared to 0 it will be set to 1 again.

Sending a Mark or Break Signal: When the TXD bit in PMR6 is cleared to 0, the TXD pin

becomes an I/O port, the level and direction (input or output) of which are determined by the

PDR and PCR bits. This feature can be used to place the TXD pin in the mark state or to send

a break signal.

To place the serial communication line in the mark (1) state before TE is set to 1, set the PDR

and PCR bits both to 1. The TXD pin becomes an I/O port outputting the value 1.

To send a break signal during transmission, set the PCR bit to 1 and clear the PDR bit to 0,

then clear the TXD bit in PMR6 to 0.

When the TXD bit in PMR6 is cleared to 0, the TXD pin becomes an I/O port outputting 0,

regardless of the current transmission status.

Receive Error Flags and Transmit Operation (Sysnchronous Mode Only): When a receive

error flag (ORER, PER, or FER) is set to 1, SCI3 will not start transmitting even if TDRE is

cleared to 0. Be sure to clear the receive error flags to 0 when starting to transmit. Note that

clearing RE to 0 does not clear the receive error flags.

Receive Data Sampling Timing and Receive Margin in Asynchronous Mode: In asynchronous

mode SCI3 operates on a base clock with 16 times the bit rate frequency. In receiving, SCI3

synchronizes internally with the falling edge of the start bit, which it samples on the base clock.

Receive data is latched at the rising edge of the eighth base clock pulse. See figure 10.24.

HD6433636SW Datasheet(PDF) 284 Page - Renesas Technology Corp