
Multiple Serial Interface
Serial Communication Interface (SCI)
68HC(9)12DG128 Rev 1.0
MOTOROLA
Multiple Serial Interface
237
11-msi
OR — Overrun Error Flag
New byte is ready to be transferred from the receive shift register to
the receive data register and the receive data register is already full
(RDRF bit is set). Data transfer is inhibited until this bit is cleared.
0 = No overrun
1 = Overrun detected
NF — Noise Error Flag
Set during the same cycle as the RDRF bit but not set in the case of
an overrun (OR).
0 = Unanimous decision
1 = Noise on a valid start bit, any of the data bits, or on the stop bit
FE — Framing Error Flag
Set when a zero is detected where a stop bit was expected. Clear the
FE flag by reading SCxSR1 with FE set and then reading SCxDR.
0 = Stop bit detected
1 = Zero detected rather than a stop bit
PF — Parity Error Flag
Indicates if received data’s parity matches parity bit. This feature is
active only when parity is enabled. The type of parity tested for is
determined by the PT (parity type) bit in SCxCR1.
0 = Parity correct
1 = Incorrect parity detected
Read anytime. Write has no meaning or effect.
RAF — Receiver Active Flag
This bit is controlled by the receiver front end. It is set during the RT1
time period of the start bit search. It is cleared when an idle state is
detected or when the receiver circuitry detects a false start bit
(generally due to noise or baud rate mismatch).
SC0SR2/SC1SR2
— SCI Status Register 2
$00C5/$00CD
Bit 7
0I
0
6
0
0
5
0
0
4
0
0
3
0
0
2
0
0
1
0
0
Bit 0
RAF
0
RESET: