Rf Unit Microprocessors And Control - Codan NGT 2010 RF Technical & Service Manual

NGT—Technical description (2010)
EEPROM
Drawing
IC16 is a serial flash ROM memory. It contains all the user settings for the system and is
read by microprocessor IC1 as required.
Tone generation
Drawing
Tone generator IC9 generates tones by dividing the clock output from IC11, which is
nominally 4 MHz, by various factors as programmed by the data inputs from the
microprocessor. IC11 also varies its output frequency of 4 MHz to extend the range of
tones. This provides the audible signals required for key beeps and warning signals at the
loudspeaker.
CAN driver
Drawing
CAN bus controller IC11 decodes the CAN protocol and passes data to and from
microprocessor IC1.
IC11 is connected to the push-pull balanced driver for the CIB IC14, which transfers data
to the RF unit. The data rate is 125 kbps.

RF unit microprocessors and control

Overview
The RF unit has five microprocessors, two of which are on the Application
Processor PCB. The first of these microprocessors is the DSP processor IC3, which
performs speech processing, ALE requirements and high-level control. The other
processor is an Application Processor IC4, which controls three slave processors on the
other PCBs. The slave processors are used for low-level control for the PCB on which
they are located.
Application Processor PCB
Drawings
CIB data from the junction box is fed via the push-pull balanced driver IC5
(drawing 04-03109) on the Audio Interface PCB to the CAN controller IC17 (sheet 2) on
the Application Processor PCB, where data is decoded for the Application Processor IC4
(sheet 1). The Application Processor then issues commands to the other microprocessors.
IC3 is a 32-bit DSP processor. IC8, IC9 and IC10 are address bus buffers. IC11 and IC12
(sheet 2) are flash memory devices that hold the main operating code. IC13 and IC14 are
SRAM devices.
98
04-03133
04-03133
04-03133
04-03108 (sheet 1) and 04-03108 (sheet 2)
NGT Transceiver System Technical Service Manual