Datasheet

Pin Name Conventions
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
Freescale Semiconductor 183
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.
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.
Table 15-1. Pin Name Conventions
Generic Pin Names RxD TxD
Full Pin Names PTE1/RxD PTE0/TxD