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

The backlighting of the LCD is achieved by a bank of LEDs mounted at the back of the
display. The intensity of the backlighting is switched from bright to medium to dark (off)
by switching V3, V4, R36, and R37.
RS232 programming port
Drawing
IC5 is a complete RS232 driver/receiver with in-built negative voltage generator.
Microprocessor IC1 receives data from IC5 and then re-transmits the data onto the
handset bus. Data received from the handset bus is transmitted by IC5.
Handset data bus
Drawing
The data bus is a push-pull balanced system and is driven from the driver IC8, which is
controlled by the microprocessor. The data bus connects to the RF unit.
RF unit—microprocessors and control
Overview
The RF unit has five microprocessors, two of which are on the Application Processor
Handset I/F 3 V PCB. The first of these microprocessors is the Digital Signal Processor
IC11, which performs speech processing, ALE requirements and high-level control
including operation of the user interface. The other processor is an 8-bit microcontroller
IC6, 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.
Handset data
2011: Drawing
2012: Drawings
Data from the handset is fed to IC6 on the Audio & Interconnect PCB (2011)/Audio
Interconnect & Data I/O PCB (2012) in the RF unit. This interfaces the push-pull
balanced data to single-ended data, which is required by the Application Processor
Handset I/F 3 V PCB (2011)/Application Processor Handset & Data I/F PCB (2012).
NGT Transceiver System Technical Service Manual
04-03125
04-03125
04-03425
04-03499 (sheet 1)
NGT—Technical description (2011/2012)
and 04-03499 (sheet 2)
125