MC68HC705MC4MP datasheet(134/180 Pages) FREESCALE

134 / 180 page

Serial Communications Interface

MC68HC705MC4 — Rev. 2.0

Serial Communications Interface

Reset sets the TC bit. Software must initialize the TC bit to logic 0 to

avoid an instant interrupt request when turning on the transmitter.

1 = No transmission in progress

0 = Transmission in progress

RDRF — Receive Data Register Full

This clearable, read-only bit is set when the data in the receive shift

interrupt request if the RIE bit in SCCR2 is also set. Clear the RDRF

bit by reading the SCSR with RDRF set, and then reading the SCDR.

Reset clears the RDRF bit.

1 = Received data available in SCDR

0 = Received data not available in SCDR

IDLE — Receiver Idle

This clearable, read-only bit is set when 10 or 11 consecutive logic 1s

appear on the receiver input. IDLE generates an interrupt request if

the ILIE bit in SCCR2 is also set. Clear the IDLE bit by reading the

SCSR with IDLE set, and then reading the SCDR. Reset clears the

IDLE bit.

1 = Receiver input idle

0 = Receiver input not idle

OR — Receiver Overrun

This clearable, read-only bit is set if the SCDR is not read before the

receive shift register receives the next word. OR generates an

interrupt request if the RIE bit in SCCR2 is also set. The data in the

shift register is lost, but the data already in the SCDR is not affected.

Clear the OR bit by reading the SCSR with OR set, and then reading

the SCRD. Reset clears the OR bit.

1 = Receiver shift register full and RDRF = 1

0 = No receiver overrun

NF — Receiver Noise Flag

This clearable, read-only bit is set when noise is detected in data

received in the SCI data register. Clear the NF bit by reading the

SCSR, and then reading the SCDR. Reset clears the NF bit.

1 = Noise detected in SCDR

0 = No noise detected in SCDR

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MC68HC705MC4MP Datasheet(PDF) 134 Page - Freescale Semiconductor, Inc