CYIL2SM1300-EVAL View Datasheet(PDF) - ON Semiconductor
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CYIL2SM1300-EVAL Datasheet PDF : 41 Pages
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Non Destructive Readout (NDR)
Figure 8. Principle of Non Destructive Readout
CYIL2SM1300AA
time
The sensor can also be read out in a nondestructive method. After a pixel is initially reset, it can be read multiple times, without being
reset. You can record the initial reset level and all intermediate signals. High light levels saturate the pixels quickly, but a useful signal
is obtained from the early samples. For low light levels, the later or latest samples must be used. Essentially, an active pixel array is
read multiple times, and reset only once. The external system intelligence interprets the data. Table 12 on page 10 summarizes the
advantages and disadvantages of nondestructive readout.
Table 12. Advantages and Disadvantages of Non Destructive Readout
Advantages
Disadvantages
Low noise, because it is true CDS
System memory required to record the reset level and the
intermediate samples
High sensitivity. The conversion capacitance is kept low.
Requires multiples readings of each pixel, so there is higher data
throughput
High dynamic range. The results include signals for short and Requires system level digital calculations
long integration times.
Note that the amount of samples taken with one initial reset is programmable in the nr_of_ndr_steps register. If nr_of_ndr_steps is
one, the sensor operates in the default method, that is one reset and one sample. This is called the disable nondestructive read out
mode.
When nr_of_ndr_steps is two, there is one reset and two samples, and so on. In the slave mode, nothing changes on the protocol of
the signals int_time_*. The sequencer suppresses the internal reset signal to the pixel array.
Sequencer
The sequencer generates the complete internal timing of the pixel array and the readout. The timing can be controlled by the user
through the SPI register settings. The sequencer operates on the same clock as the data block. This is a division by 10 of the input
clock (internally divided).
Table 13 lists the internal registers. These registers are discussed in detail in the section Detailed Description of Internal Registers on
page 15.
Table 13. Internal Registers
Block
Register Name
MBS (reserved) Fix1
Fix2
Fix3
Fix4
Fix5
Address [6..0]
0
1
2
3
4
Field
[7:0]
[7:0]
[7:0]
[7:0]
[7:0]
Reset Value
Description
0x00
Reserved, fixed value
0xFF
Reserved, fixed value
0x00
Reserved, fixed value
0x00
Reserved, fixed value
‘0x08’
Reserved, fixed value
Document Number: 001-24599 Rev. *C
Page 10 of 41
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