S912XEG128J2MAA Datasheet, PDF (726/1324 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 20 Serial Communication Interface (S12SCIV5)
20.2 External Signal Description
The SCI module has a total of two external pins.
20.2.1 TXD — Transmit Pin
The TXD pin transmits SCI (standard or infrared) data. It will idle high in either mode and is high
impedance anytime the transmitter is disabled.
20.2.2 RXD — Receive Pin
The RXD pin receives SCI (standard or infrared) data. An idle line is detected as a line high. This input is
ignored when the receiver is disabled and should be terminated to a known voltage.
20.3 Memory Map and Register Definition
This section provides a detailed description of all the SCI registers.
20.3.1 Module Memory Map and Register Definition
The memory map for the SCI module is given below in Figure 20-2. The address listed for each register is
the address offset. The total address for each register is the sum of the base address for the SCI module and
the address offset for each register.
MC9S12XE-Family Reference Manual Rev. 1.25
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Freescale Semiconductor