Figure 2-2. Astro Spectra B+ Routing For Vocoder/Controller (Vocon) Board - Motorola ASTRO Digital Spectra Service Manual

2-10
Transistor Q206 controls solid-state power switch Q207, providing SWB+ to the encryption module
(if equipped). The "SWB+" and "UNSWB+" encryption voltages both originate from pin 38 of J501
and are fed to the encryption module via J801.
Port PL3 (5-V EN) on the SLIC and Q207 are under the control of the microcontroller unit (MCU),
U204. This allows the MCU to follow an orderly power-down sequence when it senses that the B+
sense is off. This sense is provided via resistor network R222 and R223, which provides an input to
the A/D port to the MCU.
It should also be noted that a system reset is provided by the undervoltage detector, U407. This
device brings the system out of reset on power-up, and provides a system reset to the
microcomputer on power-down.
8Kx24
SRAM
U402
8Kx24
SRAM
U403
8Kx24
SRAM
U414
256Kx8
FLASH
U205
256Kx8
FLASH
U210

Figure 2-2. ASTRO Spectra B+ Routing for Vocoder/Controller (VOCON) Board

July 1, 2002
DSP56001
U405
ADSIC
U406
256Kx8
FLASH
U404
This Page Intentionally Left Blank
SRAM
U202
EEPROM
5V Digital
U201
HC11F1
SLIC IV
MCU
U206
U204
Vocoder/Controller
General Overview: Radio Power
J801
SW B+
Switch
Q207
B+_Sense
5V Analog
B+_CNTL
5V EN
B+_
Sense
J501
UNSW_B+
MAEPF-25104-O
68P81076C25-C