MC68HC08AS32 Datasheet, PDF (266/394 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

Serial Communications Interface (SCI)
SCTE — SCI Transmitter Empty Bit
This clearable, read-only bit is set when the SCDR transfers a
character to the transmit shift register. SCTE can generate an SCI
transmitter CPU interrupt request. When the SCTIE bit in SCC2 is set,
SCTE generates an SCI transmitter CPU interrupt request. In normal
operation, clear the SCTE bit by reading SCS1 with SCTE set and
then writing to SCDR. Reset sets the SCTE bit.
1 = SCDR data transferred to transmit shift register
0 = SCDR data not transferred to transmit shift register
NOTE: Setting the TE bit for the first time also sets the SCTE bit. Setting the TE
and SCTIE bits generates an SCI transmitter CPU request.
TC — Transmission Complete Bit
This read-only bit is set when the SCTE bit is set and no data,
preamble, or break character is being transmitted. TC generates an
SCI transmitter CPU interrupt request if the TCIE bit in SCC2 is also
set. TC is cleared automatically when data, preamble, or break
character is queued and ready to be sent. There may be up to 1.5
transmitter clocks of latency between queueing data, preamble, and
break character and the transmission actually starting. Reset sets the
TC bit.
1 = No transmission in progress
0 = Transmission in progress
SCRF — SCI Receiver Full Bit
This clearable, read-only bit is set when the data in the receive shift
register transfers to the SCI data register. SCRF can generate an SCI
receiver CPU interrupt request. In normal operation, clear the SCRF
bit by reading SCS1 with SCRF set and then reading the SCDR.
Reset clears SCRF.
1 = Received data available in SCDR
0 = Data not available in SCDR
IDLE — Receiver Idle Bit
This clearable, read-only bit is set when 10 or 11 consecutive logic 1s
appear on the receiver input. IDLE generates an SCI error CPU
interrupt request if the ILIE bit in SCC2 also is set and the DMARE bit
Advance Information
266
Serial Communications Interface (SCI)
MC68HC08AS32 — Rev. 3.0
MOTOROLA