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

October 28, 2002
DSP56001
U405
ADSIC
U406
256Kx8
FLASH
U404
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
6881076C25-D