Change the exposure time of camera-OV9281?

[lzbsuzhou]

I run the multi_camera_board.py, and want to change the exposure time. So I add the following code:

camera.software_auto_exposure(False)
address_h_c = c_uint16(0x3500)
address_m_c = c_uint16(0x3501)
address_l_c = c_uint16(0x3502)
expo_h_c = c_uint16(0x0000)
expo_m_c = c_uint16(0x0000)
expo_l_c = c_uint16(0x00ff)
camera.write_sensor_reg(address_h_c.value, expo_h_c.value)
camera.write_sensor_reg(address_m_c.value, expo_m_c.value)
camera.write_sensor_reg(address_l_c.value, expo_l_c.value)

The exposure time becomes lower but I don't have the detail of the exposure registor of OV9281(I can't find its datasheet). Could you add some code like setting the exposure time, gain value in your code, or tell me the detail of these registors? Thanks!