STM32H745 parallel transmission

[EsKi]

Hi, I have Interface (type MASTER) 10-bit + CLK, FCLK=~9MHz

Can I use DCMI to read 10-bit without VSYNC and HSYNC?

Or some other method? The usual assembler software method "ldr r1, [port, #....]" is too slow and despite many attempts it has not been possible to do it this way.

Cpu CLK ~400MHz, AHB4 ~200MHz, ARB4 ~100MHz

[AScha.3]

Hi,

first: what you do with the data ? (You get about 20MB/sec , cpu has ~ 1M RAM , so 1/20 sec to "full" .)

Or how much data to receive?

+

>DCMI to read 10-bit

Should work, VSYNC and HSYNC together to a pin : hi->lo starts capture (= "frame" for video)

[EsKi]

My data has frames that are easy to catch and are not long (around 1kB) and are easy to process from assemble.

Normally I could connect something to DCMI_HSYNC, but I use LCD_VSYNC on pin PA4 (I have VGA output) and I don't have an alternative to DCMI_HSYNC on another pin.

My data is similar to the DCMI interface - 8 bit + clk + hsync + vsync and it would be possible to process it using all pins, if not PA4. Unless there is a way to move LCD_VSYNC or DCMI_HSYNC to a different pin than PA4

[AScha.3]

So you cannot enable the DCMI at all, because PA4 used for LCD and no more avail for DCMI .

[EsKi]

I can not configure the pin alternatively for one of the functions, but it will not help.

So how to do fast read (9MHz) 10-bit + external CLK?

Theoretically, it should be trivially simple even in software, because data processing comes down to 2-3 AND, 2-3 SHIFT, write

[AScha.3]

Maybe try: reading port with DMA , trigger it by using a timer or exti pin (but direct, not by INT );

see

https://community.st.com/t5/stm32-mcus-products/parallel-transmission-using-gpio-and-dma-like-an4666/m-p/313866#M73322

https://www.st.com/resource/en/application_note/an4666-parallel-synchronous-transmission-using-gpio-and-dma-stmicroelectronics.pdf