Datasheet

MC68HC908GR16A Data Sheet, Rev. 1.0
Freescale Semiconductor 143
Chapter 14
Enhanced Serial Communications Interface (ESCI) Module
14.1 Introduction
The enhanced serial communications interface (ESCI) module allows asynchronous communications
with peripheral devices and other microcontroller units (MCU).
14.2 Features
Features include:
• Full-duplex operation
• Standard mark/space non-return-to-zero (NRZ) format
• Programmable baud rates
• Programmable 8-bit or 9-bit character length
• Separately enabled transmitter and receiver
• Separate receiver and transmitter central processor unit (CPU) interrupt requests
• Programmable transmitter output polarity
• Two receiver wakeup methods:
– Idle line wakeup
– Address mark wakeup
• Interrupt-driven operation with eight interrupt flags:
– Transmitter empty
– Transmission complete
– Receiver full
– Idle receiver input
– Receiver overrun
– Noise error
– Framing error
– Parity error
• Receiver framing error detection
• Hardware parity checking
• 1/16 bit-time noise detection
14.3 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 14-1 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.