mc68hc908mr32 Freescale Semiconductor, Inc, mc68hc908mr32 Datasheet - Page 174

• Manufacturer Part Number: mc68hc908mr32
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Serial Communications Interface Module (SCI)
13.7.4 SCI Status Register 1
SCI status register 1 (SCS1) contains flags to signal these conditions:
SCTE — SCI Transmitter Empty Bit
TC — Transmission Complete Bit
SCRF — SCI Receiver Full Bit
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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.
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 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.
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. When the SCRIE bit in SCC2 is
set, SCRF generates a 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 = SCDR data transferred to transmit shift register
0 = SCDR data not transferred to transmit shift register
1 = No transmission in progress
0 = Transmission in progress
1 = Received data available in SCDR
0 = Data not available in SCDR
Transfer of SCDR data to transmit shift register complete
Transmission complete
Transfer of receive shift register data to SCDR complete
Receiver input idle
Receiver overrun
Noisy data
Framing error
Parity error
Address: $003B
Reset:
Read:
Write:
SCTE
Bit 7
R
R
1
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
Figure 13-11. SCI Status Register 1 (SCS1)
= Reserved
TC
R
6
1
SCRF
R
5
0
IDLE
R
4
0
OR
R
3
0
NF
R
2
0
FE
R
1
0
Freescale Semiconductor
Bit 0
PE
R
0