Chapter 3 Controller Theory Of Operation; Controller; Microprocessor Circuitry; Table 3-1. Radio Memory Requirements - Motorola EP450 Service Manual

Chapter 3 Controller Theory of Operation

3.1

Controller

The controller provides the following functions:
• interface with controls and indicators
• serial bus control of major radio circuit blocks
• encoding and/or decoding of selective signaling formats such as PL, DPL, MDC-1200 and
QuikCall II
• interface to CPS programming via the microphone connector
• storage of customer-specific information such as channel frequencies, scan lists, and signaling
codes
• storage of factory tuning parameters such as transmitter power and deviation, receiver squelch
sensitivity, and audio level adjustments
• power-up, power-down and reset routines
Figure 6-3 (VHF) shows the interconnection between the controller and the various other radio
blocks. Figure 6-9
controller block:

• microprocessor circuitry

• audio circuitry
• DC regulation circuitry (refer to
• rotary and pushbutton controls and switches
• option board interface
The majority of the circuitry described below is contained in the (VHF) Microprocessor Circuitry
schematic diagrams
schematics (Figures
3.1.1 Microprocessor Circuitry
The microprocessor circuitry includes microprocessor (U401) and associated EEPROM, S-RAM (not
used in EP450 models), and Flash ROM memories. The following memory IC's are used:
Reference No.
U402
U403
U404
show the connections between the following circuit areas which comprise the
Chapter
(Figure 6-10). Portions are also found in the Audio and DC Regulation
6-11 and 6-12).

Table 3-1. Radio Memory Requirements

Description
Serial EEPROM
Static RAM
Flash ROM
2, DC Regulations and Distribution.)
Type
AT25128
(not used)
AT49LV001N_70 V
Size
16K x 8
128K x 8