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P7389i – Circuit Description
6) The unit will then follow on as in the sequence below:
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
On initial power up, all the keypad backlights
on, they are supported from the signal
by
BKLT_EN
(Whitecap Pin K3) through Q907.
7) 13 MHz clock. On Power Up there are 2 different reference clocks produced.
Initially, as soon as power is applied to the
supported by the
CRYSTAL_BASE
to the MAGIC DM IC, which will internally be divided by 2 to give our external
13MHz clock. This is then fed out of the MAGIC DM on Pin J6
DM_13MHz) and distributed to Whitecap Pin H10 (CLKIN), then from Whitecap
Pin B7 to GCAP II Pin F5 as GCAP_CLK. At the same time the 13MHz
Diode CR248
is producing an output. This output is controlled in the following way:
The 26MHz from
within the MAGIC DM. The 13MHz from
the phase comparator, the difference in phase produces an error voltage that is fed
Motorola Internal Use
0
50
100
150
200
250
ALRT_VCC
(MAGIC DM Pin E1) will emit a 26MHz signal
Y200
is divided down to 200 kHz and fed to a phase comparator
300
350
400
450
500
(DS500 – DS509
(B+ through Q903) and switched
MAGIC DM IC
the
CR248
is also divided down and fed in to
11
and
DS513
will be
crystal,
Y200,
(MAGIC
Varactor
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