STM32F4 with DCMI

[mm10]

Hello, we have device with very old TFT display which is dying. New one is unable to obtain. It has similar interface as DCMI: vsync, hsync, pixclk, D0-D8.

I have connected these clock/data lines to DCMI port, but interrupts was not triggered.

Here are my clock lines (from top: vsync, hsync, pix):

I suspect that timing of clock signals is not correct - compared with image I have found:

clock signal is continuous, hsync/vsync falling at the same time... Can somebody confirm this, or can somebody point me to document with detailed dcmi clock format/timing?

Thank you.
mm

[KDJEM.1]

Hello @mm10 and welcome to the community;

 

Figure 23. in AN5020 shows an example of data transfer when DCMI_VSYNC and DCMI_HSYNC are active high, and when the capture edge for DCMI_PIXCLK is the rising edge.

You need to make sure that DCMI_HSYNC and DCMI_VSYNC polarities are programmed according to the
camera module configuration. In the hardware synchronization mode (ESS = 0 in DCMI_CR), the IT_VSYNC
interrupt is generated (if enabled), even when CAPTURE = 0 in DCMI_CR. 

For more details about the DCMI clock timing, I recommend you to look at STM32F4 datasheet.

If you use STM32F437, you can refer to DS9484

I propose to disable all other sources and keep only the DCMI interrupts (or you can set the DCMI at the high priority level) to check if the problem is resolved.

 

I hope this help you. 

Thank you.

Kaouthar

[mm10]

Thank you for reply. I'm using stm32f429-disco which share DCMI pins with other devices and it seems it's not suitable for me anyhow because vsync/hsync pin can not be remap (no DCMI + display in the same time). I will need to get another board just with mcu+sdram to test it. In the meantime I got success with timers+DMA.