Serial Communications Interface Module (SCI)
MC68HC08AZ32
200
Serial Communications Interface Module (SCI)
MOTOROLA
DMATE bit. Otherwise setting the TE and SCTIE bits generates an SCI
transmitter CPU interrupt request instead of a DMA service 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. When the DMA services an SCI transmitter DMA service request,
the DMA clears the TC bit by writing to the SCDR. TC is automatically
cleared when data, preamble or break is queued and ready to be sent.
There may be up to 1.5 transmitter clocks of latency between
queueing data, preamble, and break 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 or an SCI receiver DMA service
request. When the SCRIE bit in SCC2 is set and the DMARE bit in
SCC3 is clear, SCRF generates a CPU interrupt request. With both
the SCRIE and DMARE bits set, SCRF generates a DMA service
request. In normal operation, clear the SCRF bit by reading SCS1
with SCRF set and then reading the SCDR. In DMA transfers, the
DMA clears the SCRF bit when it reads 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 ’1’s
appear on the receiver input. IDLE generates an SCI receive CPU
interrupt request if the ILIE bit in SCC2 is also set and the DMARE bit
in SCC3 is clear. Clear the IDLE bit by reading SCS1 with IDLE set
and then reading the SCDR. After the receiver is enabled, it must
receive a valid character that sets the SCRF bit before an idle
32-sci