ESP8266 Community Forum

- Sat Dec 24, 2016 12:10 am #59907 Do you think you could use a parallel to serial chip and the I2S bus to get video?

From my basic understanding of the I2S on the ESP, it can run at 80MHz, and has a FIFO buffer.
With some basic maths, and without ever doing something like this before, it sounds feasible.

Assuming bitmap and monochrome (8 bits per pixel).
80MHz = 80,000,000Hz.

80,000,000 / 8 (to get bytes) / 640 / 480 = 32.55 fps

I know there are pauses between horizontal & vertical blanks, so it will be less than that.

Does anyone know if there is any problems with using I2S to read from a parallel to serial chip like this?

- Mon Dec 26, 2016 7:50 am #59973

Do you think you could use a parallel to serial chip and the I2S bus to get video?

From my basic understanding of the I2S on the ESP, it can run at 80MHz, and has a FIFO buffer.
With some basic maths, and without ever doing something like this before, it sounds feasible.

Assuming bitmap and monochrome (8 bits per pixel).
80MHz = 80,000,000Hz.

80,000,000 / 8 (to get bytes) / 640 / 480 = 32.55 fps

I know there are pauses between horizontal & vertical blanks, so it will be less than that.

Does anyone know if there is any problems with using I2S to read from a parallel to serial chip like this?

Hi,

i'm not sure you can reach that clock frequency (80MHz) with I2S, which is a protocol intended for audio communication. Perhaps you meant I2C protocol? In that case you could in theory achieve a higher frame rate using a parallel to serial conversion IC.

Rgds.

- Mon Jan 30, 2017 5:11 pm #61797 I do mean I2S, but I don't know enough about it.
It's a hardware interface that will DMA the bits directly into a ring buffer.
It's designed for sound, but in the end it's just bits in ram, I don't think it does any pre-processing on it.
As for how fast the I2S bus can handle, I cant find any documentation.

- Mon Apr 24, 2017 11:33 am #65219 This looks very interesting, however I couldn't work out if I need an OV7670 version with or without the FIFO buffer? I stupidly ordered one without the FIFO as I didn't realise there were two types and haven't been able to use it yet.