topic MX53 CSI/IDMAC config for Aptina 12-bit grayscale camera? in i.MX Processors

MX53 CSI/IDMAC config for Aptina 12-bit grayscale camera?

EdMenard — Tue, 28 May 2013 21:33:45 GMT

Hi,

I'm having a problem configuring the MX53 CSI/IDMAC properly for a 12-bit Aptina camera - the data values are showing up in memory in bits 4-15 rather than 0-11. Here's the scenario:

MT9P031M 12-bit mono camera

parallel data connected to data 8-19

CSI0_SENS_CONF:

protocol: gated

format: generic

data width: 16 bits

data dest: IDMAC

CPMEM (interleaved):

BPP: 3 (12 bits per pixel)

NPB: 31

PFS: 6 (generic data)

Compander is disabled

I put the camera into test mode, generating a walking 1's pattern.

Here are the data values that are put in memory, which are shifted left by 4 bits:

0020

0040

0080

0100

0200

0400

0800

1000

2000

4000

8000

0010

0020

...

It's my understanding that I should be able to have 12-bit camera data show up in the lower 12 bits of memory - what additional/different settings are needed to do that...?

Thanks,

--Ed

Re: MX53 CSI/IDMAC config for Aptina 12-bit grayscale camera?

qiang_li-mpu_se — Mon, 03 Jun 2013 03:28:11 GMT

I think you also need set BPP to 16 bits per pixel in CPMEM.
For generic mode, when you set 16 bits data width in CSI, it will capture 16 bits each clock. And when use CPMEM to save them to memory, with your setting, 12 bits will be saved each time, but the captured data has 4 bits unused data, it will also be saved to memory, so there will be 4 bits shift.
And if you wants to save the 12 bits gray data to memory bits[0~11], I think you should connect the data pins to CSI_DATA15 ~ CSI_DATA4.
Otherwize, when convert from 16bits to 12bits, LSB will be dropped, so the 12 bits data will always kept in memory bits[4-15].

Re: MX53 CSI/IDMAC config for Aptina 12-bit grayscale camera?

EdMenard — Mon, 03 Jun 2013 16:00:34 GMT

Thanks - that's the conclusion we reached as well.

For now we are shifting the bits down in software - next rev of the hardware we'll connect as you suggest.