VV5409 View Datasheet(PDF) - Vision
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'VV5409' PDF : 39 Pages View PDF
VV5409 CMOS Monochrome Sensor Datasheet (Restricted) Rev 1.0
6.7.2 Single location, single data read
A read message always contains the index used to get the first byte.
Device
Start address Ack
Index
Data
Stop
S
2110
A0
3210
A
8510
AP
Figure 6.5 : Single location, single read
This example assumes that a write message has already taken place, and the residual index value is 3210.
A value of 8510 is read from the fineH exposure register. Note that the read message is terminated with a
negative acknowledge (A) from the master; it is not guaranteed that the master will be able to issue a stop
condition, at any other time during a read message. This is because, if the data sent by the slave is all zeros,
the SDA line cannot rise, which is part of the stop condition.
6.7.3 No data write, followed by same location read
When a location is to be read, but the value of the stored index is not known, a write message with no data
byte must be written first, specifying the index. The read message then completes the message sequence.
To avoid relinquishing the serial-bus to another master, a repeated start condition is asserted between the
write, and read messages. In this example, the gain value (index = 3610) is read as 1510.
No data write
Read index and data
S 2110 A 0 3610 A Sr 2110 A 0 3610 A 1510 A P
Figure 6.6 : No data write followed by same location read
As mentioned in the previous example, the read message is terminated with a negative acknowledge (A) from
the master.
6.7.4 Same location, multiple data write
It may be desirable to write a succession of data to a common location. This is useful when the status of a
bit,(e.g. requesting a new black calibration), must be toggled.
The message sequence indexes setup1 register. If bit 1 is toggled low, high low this will initiate a fresh black
calibration. This is achieved by writing three consecutive data bytes to the sensor. There is no requirement
to re-send the register index before each data byte.
S 2010
Write setup1
Toggle “Force Black Cal.”
A 0 1710 A
010
A
210
A
010 A P
Turn off ABC
Figure 6.7 : Same location multiple data write
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VV5409 CMOS Monochrome Sensor Datasheet (Restricted) Rev 1.0
6.7.5 Same location, multiple data read
When an exposure related value (fineH, fineL, coarseH, coarse L, gain, or clk_div) is written, it takes effect
on the output at the beginning of the next video frame, (remember that the application of the gain value is a
frame later than the other exposure parameters). To signal the consumption of the written value, a flag is set
when any of the exposure, or gain registers, are written, and is reset at the start of the next frame. This flag
appears in status0 register, and may be monitored by the bus master. To speed up reading from this location,
the sensor will repeatedly transmit the current value of the register, as long as the master acknowledges each
byte read.
In the next example, a fineH exposure value of 0 is written, the status register is addressed (no data byte),
and constantly read until the master terminates the read message.
Write fineL with zero
Address the status0 register
S 2010 A 0 3310 A
0
A Sr 2010 A
Read continuously...
010 A
Sr 2110 A 0 010 A
1
A
1
...until flag reset
A 1A
1
A 0 AP
Figure 6.8 : Same location, multiple data read
6.7.6 Multiple location write
If the automatic increment bit is set, (msb of the index byte), it is possible to write data bytes to consecutive,
adjacent internal registers, without having to send explicit indexes prior to sending each data byte. An auto-
increment write to the black calibration DAC registers, with their default values is shown in the following
example.
Incremental write
S 2010 A 1 11310 A
12816 A 12816
Figure 6.9 : Multiple location write
AP
6.7.7 Multiple location read
In the same manner, multiple locations can be read with a single read message. In this example the index is
written first, to ensure the exposure related registers are addressed, and then all six are read.
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