AR0330CM
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36
SENSOR FRAME RATE
The time required to read out an image frame (T
FRAME
)
can be derived from the number of clocks required to output
each image and the pixel clock.
The frame-rate is the inverse of the frame period.
fps +
1
T
FRAME
(eq. 18)
The number of clocks can be simplified further into the
following parameters:
• The number of clocks required for each sensor row
(line_length_pck) This parameter also determines the
sensor row period when referenced to the sensor
readout clock.
(T
ROW
= line_length_pck × 1/CLK_PIX)
• The number of row periods per frame
(frame_length_lines)
• An extra delay between frames used to achieve
a specific output frame period (extra_delay)
T
FRAME
+
1
CLK_PIX
(eq. 19)
(frame_length_lines line_length_pck ) extra_delay)
Figure 35. Frame Period Measured in Clocks
Vertical Blanking (VB)
Active Rows
Active Columns
Horizontal
Blanking
(HB)
extra_delay
line_length_pck = Active Columns + HB
frame_length_lines = Active Rows + VB
Row Period (T
ROW
)
The line_length_pck will determine the number of clock
periods per row and the row period (T
ROW
) when combined
with the sensor readout clock. The line_length_pck includes
both the active pixels and the horizontal blanking time per
row. The sensor utilizes two readout paths, as seen in
Figure 18, allowing the sensor to output two pixels during
each pixel clock.
The minimum line_length_pck is defined as the
maximum of the following three equations:
ADC Readout Limitation:
1024 (ADC_HIGH_SPEED) + 0
(eq. 20)
1116 (ADC_HIGH_SPEED) + 1(0)
or
Options to modify this limit, as mentioned in the
“Sequencer” section, can be found in the AR0330 Developer
Guide.
Digital Readout Limitation:
1
3
ǒ
x_addr_end * x_addr_start
(x_odd_inc ) 1) 0.5
Ǔ
(eq. 21)
Output Interface Limitations:
1
2
ǒ
x_addr_end * x_addr_start
(x_odd_inc ) 1) 0.5
Ǔ
) 96
(eq. 22)
Row Periods per Frame
The frame_length_lines determines the number of row
periods (T
ROW
) per frame. This includes both the active and
blanking rows. The minimum_vertical_blanking value is
defined by the number of OB rows read per frame, two
embedded data rows, and two blank rows.
Minimum frame_length_lines +
y_addr_end * y_addr_start
y_odd_inc)1
2
)
(eq. 23)
) minimum
vertical
blanking
The sensor is configured to output frame information in
two embedded data rows by setting R0x3064[8] to 1
(default). If R0x3064[8] is set to 0, the sensor will instead
output two blank rows. The data configured in the two
embedded rows is defined in MIPI CSI−2 Specification
V1.00.
Table 37. MINIMUM VERTICAL BLANKING CONFIGURATION
R0x3180[0x00F0]
OB Rows minimum_vertical_blanking
0x8 (Default) 8 OB Rows 8 OB + 4 = 12
0x4 4 OB Rows 4 OB + 4 = 8
0x2 2 OB Rows 2 OB + 4 = 6
The locations of the OB rows, embedded rows, and blank
rows within the frame readout are identified in Figure 36.
