SAMA5D2 ISC not working for new image sensor

Discussion around products based on ARM Cortex-A5 core.

Moderator: nferre

Posts: 4
Joined: Mon Jun 10, 2019 12:58 pm

SAMA5D2 ISC not working for new image sensor

Tue Jun 11, 2019 7:45 pm

Working with Softpack V2.13 ISC (image sensor controller) example project for SAMA5D27-SOM1-EK1. I was able to get images for one of the supported sensor (OV5640). I cannot get images for another sensor (AR0134) I am trying to incorporate. The AR0134 is not supported in the Softpack example but I have generated a configuration file for it and modified the driver code.

The modified code is working in so far as I can configure the AR0134 sensor registers, and the sensor is providing correct output (i.e.: pixel clock, frame valid, line valid, pixel data) based on probing of the SOM input pins with a logic analyzer. There are differences in the data from the sensors as summarized below. Key differences are the the non-working sensor has frame valid output signal that extends the duration of the line valid pulses for the frame. The working sensor has a short pulse at the beginning of the frame and that is it. The levels are lower for the non-working sensor (2.8 vs 3.3V).

Looking for troubleshooting guidance to determine why the new sensor (AR0134) data is not getting to DDRAM memory in the same way as the supported sensor (OV5640) when the signals appear fine. I have monitored the ISC interrupt handler, _isc_handler(), function (in iscd.c). The ISC_INTSR.DDONE bit, indicating DMA transfer was completed, is not set for non-working sensor. That is consistent with not getting data to DDRAM, but I do not understand what conditions are not met for the DMA transfer or if there is a data pipeline configuration that needs to change for the non-working sensor.

OV5640 (working) AR0134 (not working)
Master Clock 10.25 MHz @3.3V 10.25 MHz @3.3V
Pixel Clock 16 MHz @3.3V 28.2 MHz @2.8V*
Frame Valid Short 310 usec pulse @3.3V Full frame period @2.8V*
Frame Rate 11 fps 20.5 fps
Line Valid 133 usec @3.3V 49 usec @2.8V*

* AR0134 carrier PCB has 2.8V regulator.

Additional Information:
Image sensors:
OV5640 on Waveshare PCB (working) and
AR0134 on Arducam UC-403 PCB (not working)

System on Module: SAMA5D27-SOM1-EK1
Software: Softpack v2.13, ISC example
OS: Bare metal
IDE: Eclipse IDE for GNU ARM & RISC-V C/C++ Developers (2018-12)
Toolchain: GNU MCU Eclipse ARM Embedded GCC (arm-none-eabi-gcc)
Posts: 4
Joined: Mon Jun 10, 2019 12:58 pm

Re: SAMA5D2 ISC not working for new image sensor

Fri Jun 14, 2019 3:42 pm

Source of problem identified and resolved.

Some CMOS sensors transmit valid pixel information when the frame valid signal is high as opposed to low as the present Softpack v2.13 ISC example supported sensors. Added logic in function iscd_pipe_start to write the correct frame valid polarity bit to isc_pfe_set_sync_polarity function.

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