Hi All,
We are trying to interface camera on Avenger96. But we are not able to achieve maximum throughput supported by
DCMI, st-mipid02.
As per Figure 2 in stmipid02 datasheet ( Datasheet - STMIPID02 - Dual mode MIPI CSI-2 / SMIA CCP2 de-serializer),
MIPI CSI-2 to STMIPID02 data rate should be between 80Mbps to 800Mbps per lane.
DCMI operates at 208Mhz in 8 Bit mode, maximum theoretical throughput is 208 MiB/s (~1600Mbps).
In our case, we are able to get proper image only if data rate of sensor module interface is 320Mbps (set in sensor module)
and st-mipid02 data rate is set at 333Mbps (via clk_lane_reg1).
When we try to set st-mipid02 data rate to 400 or 500 Mbps per lane and data rate of camera sensor module to 380Mbps, 480Mbps respectively (which is well within range of stmipid02 and dcmi),
we are not getting proper image and we are seeing overrun errors from DCMI mentioned below.
“stm32-dcmi 4c006000.dcmi: Some errors found while streaming: errors=6963 (overrun=6966), buffers=4”
It seems that DCMI is not able to provide expected throughput. Could you please provide information on
limitations of st mipid02 and DCMI?
Also, as per mentioned in section 3.3 of AN5470 [dm00693021-stm32mp1-series-interfacing-with-a-mipi-csi2-camera-stmicroelectronics (2).pdf](file:///C:/Users/142865/AppData/Local/Microsoft/Windows/INetCache/Content.Outlook/K6NX08HM/dm00693021-stm32mp1-series-interfacing-with-a-mipi-csi2-camera-stmicroelectronics%20(2).pdf)
from ST, “maximum performance is achieved is 24MPixel/sec, which is equivalent of 1.3Mpixel @18 fps”. In this case total data rate would be ~390 Mbps if data format is 16 bit. Does that mean that we can not achieve more than 390Mbps of throughput?
