MMC2107 Datasheet, PDF (343/618 Pages) –

Freescale Semiconductor, Inc.
Serial Communications Interface Modules (SCI1 and SCI2)
Memory Map and Registers
RDRF — Receive Data Register Full Flag
The RDRF flag is set when the data in the receive shift register is
transferred to SCIDRH and SCIDRL. It signals that the received data
is available to the MCU. If the RIE bit is set in SCICR2, RDRF
generates an interrupt request. Clear RDRF by reading the SCISR1
and then reading SCIDRL. Reset clears RDRF.
1 = Received data available in SCIDRH and SCIDRL
0 = Received data not available in SCIDRH and SCIDRL
IDLE — Idle Line Flag
The IDLE flag is set when 10 (if M = 0) or 11 (if M = 1) consecutive
logic 1s appear on the receiver input. If the ILIE bit in SCICR2 is set,
IDLE generates an interrupt request. Once IDLE is cleared, a valid
frame must again set the RDRF flag before an idle condition can set
the IDLE flag. Clear IDLE by reading SCISR1 and then reading
SCIDRL. Reset clears IDLE.
1 = Receiver idle
0 = Receiver active or idle since reset or idle since IDLE flag last
cleared
NOTE: When RWU =1, an idle line condition does not set the IDLE flag.
OR — Overrun Flag
The OR flag is set if data is not read from SCIDRL before the receive
shift register receives the stop bit of the next frame. This is a receiver
overrun condition. If the RIE bit in SCICR2 is set, OR generates an
interrupt request. The data in the shift register is lost, but the data
already in the SCIDRH and SCIDRL is not affected. Clear OR by
reading SCISR1 and then reading SCIDRL. Reset clears OR.
1 = Overrun
0 = No overrun
NF — Noise Flag
The NF flag is set when the SCI detects noise on the receiver input.
NF is set during the same cycle as the RDRF flag but does not get set
in the case of an overrun. Clear NF by reading SCISR1 and then
reading SCIDRL. Reset clears NF.
1 = Noise
0 = No noise
MMC2107 – Rev. 2.0
MOTOROLA
Serial Communications Interface Modules (SCI1 and SCI2)
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Technical Data
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