MC68HC08AS32 Datasheet, PDF (175/280 Pages) Motorola, Inc – M68HC08 Family of 8-bit microcontroller units (MCUs)

12.8.4 SCI Status Register 1
SCI status register 1 contains flags to signal the following conditions:
• 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
NOTE:
Address: $0016
Bit 7
6
5
4
3
2
1
Bit 0
Read: SCTE
TC
SCRF
IDLE
OR
NF
FE
PE
Write: R
R
R
R
R
R
R
R
Reset:
1
1
0
0
0
0
0
0
R
= Reserved
Figure 12-11. SCI Status Register 1 (SCS1)
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
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
MC68HC08AS32 — Rev. 4.1
Freescale Semiconductor
Data Sheet
175