Motorola Symbol SE4400, Руководство по интеграции

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5-9
Application Notes
Mode 1
Startup Procedure
See Figure 5-4 for the Mode 1 startup procedure timing diagram.
The Vcc supply voltage and REG_RES* reset line requirements are the same in Mode 1 as
in Mode 3.
After a successful reset, the I
2
C registers contain default parameters that place the
SE4400 in stand-by mode. Initialize the SE4400 using the register values listed in Table A-
3 . This I
2
C programming can be performed as soon as the SE4400 is reset, and typically
takes about 31 ms.
The master clock input, MCKI, should begin immediately following the initial I
2
C
programming, but can begin earlier. The frequency of MCKI can be between 10MHz and
12.727MHz; 12MHz is recommended. If the system must run at a slower frequency, adjust
the I
2
C registers according to LC99704B-WK3 Sanyo DSP Specification , Version 1 .
Minimize the jittering of MCKI as the SE4400 is sensitive to this.
The charge pump, which generates ±5 V so that the charge can be properly shifted out of
the CCD sensor, takes about 15 frame times to arrive at regulation. There is no way to
shorten this time in Mode 1. For the first 15 frames the images may begin dark and
progressively get lighter as the charge pump is charged to full capacity.
If toggle mode is used (see Motor Control on page 5-16) and tracking of the motor position
is desired, set the focus motor in a known initial state at least 20 ms before the first
exposure period to track the focus position as it is changed in each frame.