Codan NGT 2010 RF Technical & Service Manual page 660

NRI—Technical description
Serial interfaces
The NRI uses RS232-style serial ports as interfaces for the line modem and test port. The
main microcontroller used in the NRI (Hitachi H8/3003) only supports two simple serial
interfaces. A DUART is used in conjunction with the processor to provide two additional
RS232 serial interfaces. Level translation from TTL level to RS232 level is
accomplished by IC103 and IC104, located on the NRI User Connect PCB.
Microprocessor control
A 16-bit H8/3003 Hitachi microcontroller (IC203) controls the NRI. The H8/3003
executes from program memory stored in an 8 Mbps flash device (IC209), while a
4 Mbps static memory (IC206) is used during program execution for temporary variable
storage. A non-volatile memory storage device (IC207) provides storage for
configuration parameters that must be retained after a loss of power to the system.
Microcontroller IC203 accesses the serial interfaces either directly or through DUART
IC201, and CAN data is accessed through IC208, SJA1000 CAN controller. System
audio control is achieved through a 3-wire serial interface to the programmable logic
device.
266 NGT Transceiver System Technical Service Manual