Document No. 002-14949 Rev. *E
Page 49 of 113
PRELIMINARY
CYW43353
Figure 25. WLAN Boot-Up Sequence
<
950
µs
After
8
ms
the
reference
clock
is
assumed
to
be
up.
Access
to
PLL
registers
is
possible.
8
ms
<
4
ms
<
104
ms
After
a
fixed
delay
following
Internal
POR
and
WL_REG_ON
going
high,
the
device
responds
to
host
F0
(address
0x14)
reads.
VDDIO
WL_REG_ON
VDDC
(from
internal
PMU)
Internal
POR
Device
requests
for
reference
clock
Host
Interaction:
Host
polls
F0
(address
0x14)
until
it
reads
a
predefined
pattern.
Host
sets
wake
‐
up
‐
wlan
bit
and
waits
8
ms,
the
maximum
time
for
reference
clock
availability.
After
8
ms,
host
programs
PLL
registers
to
set
crystal
frequency
Host
downloads
code.
Chip
active
interrupt
is
asserted
after
the
PLL
locks
VBAT*
*Notes:
1.
VBAT
should
not
rise
10%–90%
faster
than
40
microseconds.
2.
VBAT
should
be
up
before
or
at
the
same
time
as
VDDIO.
VDDIO
should
NOT
be
present
first
or
be
held
high
before
VBAT
is
high.