Hello,

just a quick question because it is confusing to me that I can’t get the documentation for sensor driver development and the imx219 example aligned. I get it why we need gain/framerate/exposure factor to convert floating point values to fixed signed. It makes total sense. But with exposure in the documentation it says the value should be in microseconds.

Minimum exposure time limit for the mode, in microseconds. The value is rounded up to an integer.

This value is calculated from:

minimum exposure time in float = (minimum coarse integration time) * line_length / pix_clk_hz * 1000000

The value specified must be multiplied by exposure_factor.

min_exp_time = (minimum exposure time in float) * exposure_factor

But if the value should be in the end in microseconds that would mean I have to set it to the value in microseconds multiplied by the framerate factor. And who wants to set exposure time in fractions of microseconds? :D

Since in the imx219 example the value specified is even lower than the exposure_factor I assume we are talking about seconds, which become microseconds if we use an exposure_factor of 1,000,000, right? So in that case I guess the documentation is kind of misleading.

Correct me if I am wrong.

Best regards,

jb

mode0 { /* IMX219_MODE_3264x2464_21FPS */

mclk_khz = “24000”;

num_lanes = “2”;

tegra_sinterface = “serial_a”;

phy_mode = “DPHY”;

discontinuous_clk = “yes”;

dpcm_enable = “false”;

cil_settletime = “0”;`active_w = "3264"; active_h = "2464"; pixel_t = "bayer_rggb"; readout_orientation = "90"; line_length = "3448"; inherent_gain = "1"; mclk_multiplier = "9.33"; pix_clk_hz = "182400000"; gain_factor = "16"; framerate_factor = "1000000"; exposure_factor = "1000000"; min_gain_val = "16"; /* 1.00x */ max_gain_val = "170"; /* 10.66x */ step_gain_val = "1"; default_gain = "16"; /* 1.00x */ min_hdr_ratio = "1"; max_hdr_ratio = "1"; min_framerate = "2000000"; /* 2.0 fps */ max_framerate = "21000000"; /* 21.0 fps */ step_framerate = "1"; default_framerate = "21000000"; /* 21.0 fps */ ** min_exp_time = "13"; ** /* us */ ** max_exp_time = "683709";** /* us */ step_exp_time = "1"; default_exp_time = "2495"; /* us */ embedded_metadata_height = "2"; };`