MC68HC11E0 Motorola, MC68HC11E0 Datasheet - Page 45

• Manufacturer Part Number: MC68HC11E0
• Description: (MC68HC711E Series) M68HC11E Series Programming Reference Guide
• Manufacturer: Motorola

Serial Communications Interface Data Register (SCDR)
Serial Communications Interface Status Register (SCSR)
MOTOROLA
Address: $102F
R[7:0]/T[7:0] — Receiver/Transmitter Data Bits [7:0]
Address: $102E
TDRE — Transmit Data Register Empty Flag
TC — Transmit Complete Flag
RDRF — Receive Data Register Full Flag
IDLE — Idle Line Detected Flag
Reset:
Reset:
Read:
Write:
Read:
Write:
M68HC11E Series Programming Reference Guide
Receive and transmit are double buffered. Reads access the receive data
buffer, and writes access the transmit data buffer. When the M bit in SCCR1
is set, R8 and T8 in SCCR1 store the ninth bit in receive and transmit data
characters.
This flag is set when SCDR is empty. Clear the TDRE flag by reading SCSR
with TDRE set and then writing to SCDR.
This flag is set when the transmitter is idle (no data, preamble, or break
transmission in progress). Clear the TC flag by reading SCSR with TC set
and then writing to SCDR.
This flag is set if a received character is ready to be read from SCDR. Clear
the RDRF flag by reading SCSR with RDRF set and then reading SCDR.
This flag is set if the RxD line is idle. Once cleared, IDLE is not set again until
the RxD line has been active and becomes idle again. The IDLE flag is
inhibited when RWU = 1. Clear IDLE by reading SCSR with IDLE set and
then reading SCDR.
0 = SCDR busy
1 = SCDR empty
0 = Transmitter busy
1 = Transmitter idle
0 = SCDR empty
1 = SCDR full
0 = RxD line active
1 = RxD line idle
R7/T7
TDRE
Bit 7
Bit 7
1
I
= Unimplemented
R6/T6
TC
6
6
1
I
RDRF
R5/T5
5
5
0
I
R4/T4
IDLE
4
4
0
I
R3/T3
OR
3
3
0
I
R2/T2
NF
2
2
0
I
M68HC11E Series Registers
R1/T1
FE
M68HC11ERG/AD
1
1
0
I
R0/T0
Bit 0
Bit 0
0
I
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