topic Re: [imx6Dual] CM-FX6 Parallel Camera Input 16bit DataBus with CSI/IPU in i.MX Processors

[imx6Dual] CM-FX6 Parallel Camera Input 16bit DataBus with CSI/IPU

francescoprospe — Fri, 28 Jun 2013 10:20:15 GMT

Hi,

we are planning to buy an imx6Dual based board and the primary goal is to acquire frames

from a parallel camera connected through a 16bit data bus clocking it at 100MHz (tentatively).

What I know is, in general, that frame acquisition is performed using the CSI interface of the IPU.

[ALERT - noob level questions below]

First, is there some kind of tutorial available, covering (at least) the macro steps to be done?

Based on the reference manual, CSI_DATA_WIDTH can clearly be set from 8 to 16 bits. Again, in the RM it is intended "for color".

Using a RGB565 as CSI_SENS_DATA_FORMAT, shouldn't a pixel be acquired in one clock tick?

It is better so set it as "Generic Data" ?

and last, in the Linux IPU driver I see that:

arch/arm/plat-mxc/include/mach/ipu-v3.h +424

/*!
* Enumeration of CSI data bus widths.
*/
enum {
        IPU_CSI_DATA_WIDTH_4,
        IPU_CSI_DATA_WIDTH_8,
        IPU_CSI_DATA_WIDTH_10,
        IPU_CSI_DATA_WIDTH_16,
};

so it should be supported low level but IPU_CSI_DATA_WIDTH_16 has no use throughout all my current kernel tree.

Conclusive question:

Is this acquisition (at 100MHz) possible? or should I limit the databus to more standard (8/10 bit) data bus?

Thanks for any illuminated soul for the time.

Francesco

Re: [imx6Dual] CM-FX6 Parallel Camera Input 16bit DataBus with CSI/IPU

Rodrigue — Thu, 18 Jul 2013 12:03:29 GMT

Hi Francesco,

Actually the CSI 16bit is only supported as generic data see chapter 37.4.3.9.

So yes, limit the bus to 8-bit and it should work.

br,

Rod

Re: [imx6Dual] CM-FX6 Parallel Camera Input 16bit DataBus with CSI/IPU

francescoprospe — Thu, 18 Jul 2013 12:29:57 GMT

Hi Rodrgue,

and thanks for the reply.

As generic data input should it be possible to acquire the frame @100MHz and then postprocess it

as generic data from ram? and is it currently supported in the kernel?

Re: [imx6Dual] CM-FX6 Parallel Camera Input 16bit DataBus with CSI/IPU

Rodrigue — Thu, 18 Jul 2013 13:24:18 GMT

Actually as you mentioned there is no mention in the driver of any defines indicating that there is a support to process 16-bit CSI data. This is a limitation of the BSP.

This is why I advise to go for 8-bit, as this should be supported. At least I know that in the latest BSP, there is support for 2 cameras, one of them being the 8-bit CSI as YUV.

Regarding the speed, everything derives from HSP_CLK see in IPU_CSI0_SENS_CONF. It can go up to 264MHz.

So I do not see a limitation here at least.