SH7708 Datasheet, PDF (360/625 Pages) Renesas Technology Corp – SuperH™ RISC engine

Bit 7: TDRE
0
1
Description
SCTDR contains valid transmit data.
TDRE is cleared to 0 when software reads TDRE after it has been set to 1, then
writes 0 in TDRE, or data is written in SCTDR.
SCTDR does not contain valid transmit data.
value)
(Initial
TDRE is set to 1 when the chip is reset or enters standby mode, the TE bit in the
serial control register (SCSCR) is cleared to 0, or SCTDR contents are loaded into
SCTSR, so new data can be written in SCTDR.
Bit 6—Receive Data Register Full (RDRF): Indicates that SCRDR contains received data.
Bit 6: RDRF Description
0
SCRDR does not contain valid received data.
value)
(Initial
RDRF is cleared to 0 when the chip is reset or enters standby mode, software
reads RDRF after it has been set to 1, then writes 0 in RDRF, or data is read from
SCRDR.
1
SCRDR contains valid received data.
RDRF is set to 1 when serial data is received normally and transferred from
SCRSR to SCRDR.
Note: SCRDR and RDRF are not affected by detection of receive errors or by clearing of the RE bit
to 0 in the serial control register. They retain their previous contents. If RDRF is still set to 1
when reception of the next data ends, an overrun error (ORER) occurs and the receive data
is lost.
Bit 5—Overrun Error (ORER): Indicates that data reception aborted due to an overrun error.
Bit 5: ORER
0
1
Description
Receiving is in progress or has ended normally.
value)
(Initial
Clearing the RE bit to 0 in the serial control register does not affect the ORER bit,
which retains its previous value.
ORER is cleared to 0 when the chip is reset or enters standby mode or software
reads ORER after it has been set to 1, then writes 0 in ORER.
A receive overrun error occurred.
SCRDR continues to hold the data received before the overrun error, so
subsequent receive data is lost. Serial receiving cannot continue while ORER is
set to 1. In synchronous mode, serial transmitting is also disabled.
ORER is set to 1 if reception of the next serial data ends when RDRF is set to 1.
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