MT9J003
www.onsemi.com
33
Table 15. SUBSAMPLING COMBINATIONS
Skip Y
Skip X Bin X Bin XY Sum X Sum XY
1
1 – – – –
2 Y – Y –
4 Y – Y –
2
1 – – – Y
2 Y Y Y Y
4 Y Y Y Y
4
1 – – – Y
2 Y Y Y Y
4 Y Y Y Y
8
1 – – – Y
2 Y – Y Y
4 Y – Y Y
16
1 – – – Y
2 Y – Y Y
4 Y – Y Y
32
1 – – – Y
2 Y – Y Y
4 Y – Y Y
Frame Rate Control
The frame-time is calculated as the row-time multiplied
by the number of rows (frame_length_lines). The row-time
is referred to in these calculations as the number of pixel
clocks read per row (line_length_pck) multiplied by the
vt_pix_clk frequency.
The formulas for calculating the frame rate of the
MT9J003 are shown below.
The line length is programmed in pixel clock periods
through the register line_length_pck. The minimum value
can be determined as the largest value found in Equation 8.
These are the required values for either the array readout or
the bandwidth available to the parallel or serial interface.
Absolute Minimum Array Line Length Pck
minimum line_length_pck = min_line_length_pck (see
Table 16, “Minimum Row Time and Blanking Numbers”)
Array Readout Line Length Pck
ȧ
ȱ
Ȳ
x_addr_end–x_addr_start ) x_odd_inc
2x(
x_odd_inc)1
2
)
) min_line_blanking_pck
ȧ
ȳ
ȴ
(eq. 8)
Interface Line Length Pck
x_output_size
ǒ
op_pix_clk
vt_pix_clk
Ǔ
) 30 (For Parallel)
(eq. 9)
ǒ
x_output_size
4
Ǔ
op_pix_clk
vt_pix_clk
) 30 (ForHiSPi)
(eq. 10)
Note that line_length_pck will be the maximum of the
three equations. The second equation describes the
limitations from the readout of the pixel array while the third
determines the frame-rate of the output interface. The
frame-rate using HiSPi will always be higher than using the
parallel interface. Values for min_line_blanking_pck are
provided in “Minimum Row Time”.
The frame length is programmed directly in number of
lines in the register frame_line_length. For a specific
window size, the minimum frame length is shown in
Equation 11:
minimumframe_length_lines +
ǒ
y_addr_end * y_addr_start ) 1
subsampling factor
) min_frame_blanking_lines
Ǔ
(eq. 11)
