HWACC CDM (Change Detection Module)

[CEGC2024]

Hi all,

I've been experimenting with the WE2 and would like to make use of the CDM for motion detection. Is the CDM functional with the SDK at this point in time? I see it is included and presumably initialized with some of the DP path functions such as sensordplib_set_INT1_HWACC however hx_drv_cdm_get_enable always returns CDM_ENABLE_OFF.

I am also a bit confused about the memory/address allocation to WDMA1. Is this shared by both the HW2x2 and CDM? How do I access the meta data of the CDM?

Thank you.

[kris-himax]

Hi @CEGC2024

1. If you want to use CDM, then SENSORDPLIB_PATH_E in cisdp_dp_init should be set so that the dp path passes through CDM.
   SENSORDPLIB_PATH_INP_HW2x2_CDM or SENSORDPLIB_PATH_INP_CDM ...
   https://github.com/HimaxWiseEyePlus/Seeed_Grove_Vision_AI_Module_V2/blob/main/EPII_CM55M_APP_S/library/sensordp/inc/sensor_dp_lib.h#L184
2. You can reference following SENSORDPLIB_PATH_E about CDM. At WE2 hardware, the data path is HW2x2 -> CDM -> WDMA1.
   If you enable CDM and you want to access the meta data of the CDM, you can just access WDMA1 and the HW2x2 result won't be stored at WDMA1 after CDM.

SENSORDPLIB_PATH_INP_HW2x2_CDM,   			/*!< Enum Datapath U2: Sensor --> INP --> 2x2 block --> CDM --> WDMA1. */
SENSORDPLIB_PATH_INP_CDM,					/*!< Enum Datapath D2: Sensor --> INP --> CDM --> WDMA1. */