Datasheet

Serial Communication Interface (SCI)
M68HC12B Family Data Sheet, Rev. 9.1
Freescale Semiconductor 199
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 0 is detected where a stop bit was expected. Clear the FE flag by reading SC0SR1 with
FE set and then reading SC0DR.
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 SC0CR1.
0 = Parity correct
1 = Incorrect parity detected
14.2.3.5 SCI Status Register 2
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).
0 = Character is not being received.
1 = Character is being received.
Address: $00C5
Bit 7654321Bit 0
Read:0000000RAF
Write:
Reset:00000000
= Unimplemented
Figure 14-8. SCI Status Register 2 (SC0SR2)