h8s-2649 Renesas Electronics Corporation., h8s-2649 Datasheet - Page 452

• Manufacturer Part Number: h8s-2649
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 13 Serial Communication Interface (SCI)
13.9
13.9.1
SCI operation can be disabled or enabled using the module stop control register. The initial setting
is for SCI operation to be halted. Register access is enabled by clearing module stop mode. For
details, see section 21, Power-Down Modes.
13.9.2
When framing error detection is performed, a break can be detected by reading the RxD pin value
directly. In a break, the input from the RxD pin becomes all 0s, setting the FER flag, and possibly
the PER flag. Note that as the SCI continues the receive operation after receiving a break, even if
the FER flag is cleared to 0, it will be set to 1 again.
13.9.3
When TE is 0, the TxD pin is used as an I/O port whose direction (input or output) and level are
determined by DR and DDR. This can be used to set the TxD pin to mark state (high level) or send
a break during serial data transmission. To maintain the communication line at mark state until TE
is set to 1, set both DDR and DR to 1. As TE is cleared to 0 at this point, the TxD pin becomes an
I/O port, and 1 is output from the TxD pin. To send a break during serial transmission, first set
DDR to 1 and DR to 0, and then clear TE to 0. When TE is cleared to 0, the transmitter is
initialized regardless of the current transmission state, the TxD pin becomes an I/O port, and 0 is
output from the TxD pin.
13.9.4
Transmission cannot be started when a receive error flag (ORER, PER, or FER) is set to 1, even if
the TDRE flag is cleared to 0. Be sure to clear the receive error flags to 0 before starting
transmission. Note also that receive error flags cannot be cleared to 0 even if the RE bit is cleared
to 0.
Rev. 2.00 Dec. 05, 2005 Page 414 of 724
REJ09B0200-0200
Usage Notes
Module Stop Mode Setting
Break Detection and Processing
Mark State and Break Detection
Receive Error Flags and Transmit Operations (Clocked Synchronous Mode Only)