CYII5FM1300AB Datasheet, PDF (18/40 Pages) Cypress Semiconductor – 1.3 MP CMOS Image Sensor

IBIS5-B-1300 CYII5FM1300AB
Figure 22. Synchronous Shutter: Pixel Read Out
Synchronous Shutter: Pixel Readout
Basic Operation
Y_START and Y_CLOCK must change on the falling edge of the
SYS_CLOCK (Tsetup and Thold > 7.5 ns). Make certain that the
pulse width is a minimum of one clock cycle for Y_CLOCK and
three clock cycles for Y_START. As long as Y_CLOCK is applied,
the sequencer stays in a suspended state. (See Figure 22.)
T₁—Row blanking time: During this period, the X-sequencer
generates the control signals to sample the pixel signal and pixel
reset levels (double sampling fpn-correction), and starts the
readout of one line. The row blanking time depends on the granu-
larity of the X-sequencer clock (see Table 15).
Table 15. Row Blanking Time as Function of X-Sequencer
Granularity
Granularity
N_GRAN
x4
x8
x 16
x 32
T₁(µs)
= 35 x N_GRAN x T_{SYS_CLOCK}
140 x T_{SYS_CLOCK} = 3.5
280 x T_{SYS_CLOCK} = 7.0
560 x T_{SYS_CLOCK} = 14.0
1120 x T_{SYS_CLOCK} = 28.0
GRAN_X_SEQ
MSB/LSB
00
01
10
11
T₂—Pixels counted by pixel counter until the value of
NROF_PIXELS register is reached. PIXEL_VALID goes high
when the internal X_SYNC signal is generated, in other words
when the readout of the pixels is started. PIXEL_VALID goes low
when the pixel counter reaches the value loaded in the
NROF_PIXELS register (after a complete row read out).
T₃—LAST_LINE goes high when the line counter reaches the
value loaded in the NROF_LINES register and stays high for one
line period (until the next falling edge of Y-CLOCK).
On Y_START the left Y-shift-register of the image core is loaded
with the YL-pointer that is loaded in to register YL_REG.
Pixel Output
The pixel signal at the PXL_OUT1 output becomes valid after
five SYS_CLOCK cycles when the internal X_SYNC (= start of
PIXEL_VALID output or external X_LOAD pulse) pulse is
asserted. (See Figure 23.)
T₁—Row blanking time (see Table 15).
T₂—5 SYS_CLOCK cycles.
T₃—Time for new X-pointer position upload in X_REG register
(see “Windowing in X-direction” on page 20 for more details).
Figure 23. Pixel Output
Document #: 38-05710 Rev. *C
Page 18 of 40