Motorola 38C V100 Service Manual page 20

Circuit Description
16
GCAP II Pin D6.
Once a power source has been selected, PWR_SW must be toggled low. This can be
done by pressing power key S500 to create ON_2, which is supported by PWR_SW
(GCAP II Pin C8). ON_2 is also pulled low when an external [fast] charger is
plugged in, providing a battery is present. (See also "Charger Circuit" on page 18.)
The power-up sequence continues as shown in Figure 8.
0 50
RESET
EPROM CE
SRAM VB&LB
SPI_CE GCAP
R/W
SPI_CE MAGIC
CLK SELECT
VCLK
BFSR 1.7 after RESET, BCKLR at 1.6s
DSC_EN
DOWNLINK
V1
UPLINK
Figure 8. Power-up Sequence Timing Diagram
On initial power up, all the keypad backlights (DS500 - DS509 and DS512 - DS522)
and display backlights (DS504 - DS510 on the antenna board in flip housing) are
turned on. They are supported by the signal ALRT_VCC (B+ through Q903) and
switched by BKLT_EN (Whitecap IC Pin K3) through Q907.
MOTOROLA CONFIDENTIAL - PROPRIETARY
November 20, 2000
100 150 200 250 300 350
Product Family 38C
400 450 500
6881036B20
000720-O