MMC2114 MOTOROLA [Motorola, Inc], MMC2114 Datasheet - Page 393

• Manufacturer Part Number: MMC2114
• Description: M CORE Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

17.14 Loop Operation
MMC2114 • MMC2113 • MMC2112 — Rev. 1.0
MOTOROLA
Serial Communications Interface Modules (SCI1 and SCI2)
In loop mode (LOOPS = 1, RSRC = 0), the transmitter output goes to the
receiver input. The RXD pin is disconnected from the SCI and is
available as a general-purpose I/O pin.
Setting the DDR bit for the TXD pin connects the transmitter output to the
TXD pin. Clearing the data direction bit disconnects the transmitter
output from the TXD pin.
Enable loop operation by setting the LOOPS bit and clearing the RSRC
bit in SCICR1. Setting the LOOPS bit disables the path from the RXD pin
to the receiver. Clearing the RSRC bit connects the transmitter output to
the receiver input. Both the transmitter and receiver must be enabled
(TE = 1 and RE = 1).
The WOMS bit in SCICR1 configures the TXD pin for full CMOS drive or
for open-drain drive. WOMS controls the TXD pin during both normal
operation and loop operation.
Freescale Semiconductor, Inc.
TXD SCIDDR
TXD SCIDDR
For More Information On This Product,
Figure 17-26. Loop Operation (LOOPS = 1, RSRC = 0)
BIT = 1
BIT = 0
Go to: www.freescale.com
TRANSMITTER
TRANSMITTER
RECEIVER
RECEIVER
Serial Communications Interface Modules (SCI1 and SCI2)
H
WOMS
WOMS
TXD
RXD
TXD
RXD
GENERAL-PURPOSE I/O
GENERAL-PURPOSE I/O
Advance Information
Loop Operation
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