Reset Circuits; Table 3-11. Integrated Circuits Voltages - Motorola ASTRO XTL 1500 Detailed Service Manual

3-66
The various voltages used by the ICs on the main board are shown in
Integrated Circuit UNSW5V
Patriot
Microprocessor
Flash
SRAM
A/D
D/A
Modulation D/A
Urchin
RS-232 XCVR
USB XCVR
Audio PA
CODEC
Amplifiers, EPOTs
555 Timer U0506-4
SB9600 MUX
Volume Pot
32K Crystal
Modulation MUX
Power Control
Keyed 9.1 V Switch

3.14.3 Reset Circuits

The reset circuits consist of the power-on reset (POR*) circuit
and SB9600 bus reset circuit. These circuits allow the microprocessor to recover from an unstable
condition, such as removing battery A+ from the radio while it is on, battery voltage too low, and
miscommunication to remote devices on the SB9600 bus, as well as generally monitoring the power
on/off condition.
June 15, 2005

Table 3-11. Integrated Circuits Voltages

SW 5V A+ 3.0 V
U0953-28
U0959-4
U0305-16
U0204-7
U606-16
U0206-7
Theory of Operation: Controller Section
Table 3-11.
9.3 V_T
2.85 V 1.85 V
X
U100 U100
U102
U103
U0900-3
FL0900-4
U0901
U0304-7
U200-6
U0201-4
U0202-3
Y0100-5
U0902-16
U0956-4
U0957-4
U0960-4
Q0952
(Figure 3-45), SW_B+ sense circuit,
1.55 V
U100
6815854H01-A