MC68HC812A4 Datasheet, PDF (254/342 Pages) Motorola, Inc – 16-bit device composed of standard on-chip peripheral modules connected by an intermodule bus. Modules include

Serial Communications Interface Module (SCI)
RWU enables the wakeup function and inhibits further receiver
interrupt requests. Normally, hardware wakes the receiver by
automatically clearing RWU.
SBK — Send Break Bit
Toggling SBK sends one break character (10 or 11 logic 0s). As long
as SBK is set, the transmitter sends logic 0s.
1 = Transmit break characters
0 = No break characters
14.7.4 SCI Status Register 1
SCI0: $00C4
SCI1: $00CC
Bit 7
6
5
4
3
2
1
Bit 0
Read: TDRE
TC
RDRF IDLE
OR
NF
FE
PF
Write:
Reset: 1
1
0
0
0
0
0
0
= Unimplemented
Figure 14-21. SCI Status Register 1 (SC0SR1 or SC1SR1)
Read: Anytime
Write: Has no meaning or effect
TDRE — Transmit Data Register Empty Flag
TDRE is set when the transmit shift register receives a byte from the
SCI data register. Clear TDRE by reading SCI status register 1 with
TDRE set and then writing to the low byte of the SCI data register.
1 = Transmit data register empty
0 = Transmit date register not empty
TC — Transmission Complete Flag
TC is set when the TDRE flag is set and no data, preamble, or break
character is being transmitted. When TC is set, the TXD pin becomes
idle (logic 1). Clear TC by reading SCI status register 1 with TC set
MC68HC812A4 — Rev. 3.0
254
Serial Communications Interface Module (SCI)
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