MC912DG128A Motorola, MC912DG128A Datasheet - Page 228

• Manufacturer Part Number: MC912DG128A
• Description: Microcontrollers
• Manufacturer: Motorola

SC0CR1/SC1CR1 — SCI Control Register 1
Multiple Serial Interface
MC68HC912DT128A Rev 2.0
228
RESET:
LOOPS
Bit 7
0
WOMS
6
0
Read or write anytime.
LOOPS — SCI LOOP Mode/Single Wire Mode Enable
WOMS — Wired-Or Mode for Serial Pins
If the DDRS bit associated with the TXD pin is set during the LOOPS
= 1, the TXD pin outputs the SCI waveform. If the DDRS bit
associated with the TXD pin is clear during the LOOPS = 1, the TXD
pin becomes high (IDLE line state) for RSRC = 0 and high impedance
for RSRC = 1. Refer to
This bit controls the two pins (TXD and RXD) associated with the SCIx
section.
0 = SCI transmit and receive sections operate normally.
1 = SCI receive section is disconnected from the RXD pin and the
0 = Pins operate in a normal mode with both high and low drive
1 = Each pin operates in an open drain fashion if that pin is
RSRC
5
0
RXD pin is available as general purpose I/O. The receiver input
is determined by the RSRC bit. The transmitter output is
controlled by the associated DDRS bit. Both the transmitter
and the receiver must be enabled to use the LOOP or the
single wire mode.
capability. To affect the RXD bit, that bit would have to be
configured as an output (via DDRS0/2) which is the single wire
case when using the SCI. WOMS bit still affects
general-purpose output on TXD and RXD pins when SCIx is
not using these pins.
declared as an output.
Multiple Serial Interface
M
4
0
WAKE
Table
3
0
34.
ILT
2
0
PE
1
0
Bit 0
PT
0
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