MC68HC908GZ16 Datasheet, PDF (185/314 Pages) Motorola, Inc – Microcontrollers

Pin Name Conventions
15.3 Pin Name Conventions
The generic names of the ESCI input/output (I/O) pins are:
• RxD (receive data)
• TxD (transmit data)
ESCI I/O lines are implemented by sharing parallel I/O port pins. The full name of an ESCI input or output
reflects the name of the shared port pin. Table 15-1 shows the full names and the generic names of the
ESCI I/O pins. The generic pin names appear in the text of this section.
Table 15-1. Pin Name Conventions
Generic Pin Names
Full Pin Names
RxD
PTE1/RxD
TxD
PTE0/TxD
15.4 Functional Description
Figure 15-2 shows the structure of the ESCI module. The ESCI allows full-duplex, asynchronous, NRZ
serial communication between the MCU and remote devices, including other MCUs. The transmitter and
receiver of the ESCI operate independently, although they use the same baud rate generator. During
normal operation, the CPU monitors the status of the ESCI, writes the data to be transmitted, and
processes received data.
The baud rate clock source for the ESCI can be selected via the configuration bit, ESCIBDSRC, of the
CONFIG2 register ($001E).
For reference, a summary of the ESCI module input/output registers is provided in Figure 15-3.
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 1
Freescale Semiconductor
185