Available camera memory and processor speed

kwf

72

Available camera memory and processor speed

« on: 14 / January / 2008, 07:54:13 »

Advertisements

Asking myself if it would be possible to port some useful programs for the CHDK hack, i wonder about the available resources:

1) How many RAM is available on these canon cameras. On my A570IS it says there is 534K free memory. Is that the normal amount, how many memory is allocated by buffers, etc.? I thought there would be at least a buffer great enough for one picture.

2) What about the processor performance? ARM9 with how many MHz?

Logged

a710is

250
A710 IS

Re: Available camera memory and processor speed

« Reply #1 on: 14 / January / 2008, 08:01:16 »

btw: howcome Canon left so much free RAM that it is able to load the CHDK on its current size and still leave free space allowing for the CHDK to get even bigger.
I mean as Canon didn't design these cameras with concerns about leaving available RAM for extra software, howcome they didn't make the RAM just big enough to fit the original Canon firmware?
and yea, what is the entire size of the RAM?
we're all glad that they've left free RAM though

Logged

GrAnd

916
[A610, S3IS]

Re: Available camera memory and processor speed

« Reply #2 on: 14 / January / 2008, 08:11:37 »

Quote from: a710is on 14 / January / 2008, 08:01:16

and yea, what is the entire size of the RAM?

32Mb. At least the first 32Mb of memory is readable.
Also, there should be a buffer memory. Also there is a memory for RAW data.

Logged

CHDK Developer.

a710is

250
A710 IS

Re: Available camera memory and processor speed

« Reply #3 on: 14 / January / 2008, 08:19:48 »

I thought it was smaller. then I guess that the memory is pretty full but empty enough for CHDK

Logged

jeff666

181
A720IS

Re: Available camera memory and processor speed

« Reply #4 on: 14 / January / 2008, 08:27:28 »

Quote from: GrAnd

Also, there should be a buffer memory. Also there is a memory for RAW data.

Do you know how the raw-data gets to its location? Is it copied by some task or does the hardware mmap it there?

Cheers.

Logged

GrAnd

916
[A610, S3IS]

Re: Available camera memory and processor speed

« Reply #5 on: 14 / January / 2008, 08:40:03 »

There should be a PDF-file (was made by someone) with camera memory map, but, unfortunately, I'm not able to find it.

Quote from: jeff666 on 14 / January / 2008, 08:27:28

Do you know how the raw-data gets to its location? Is it copied by some task or does the hardware mmap it there?

Actually, I don't know. I think the second. At least it sounds reasonable.

Logged

CHDK Developer.

DataGhost

314
EOS 40D, S5IS

Re: Available camera memory and processor speed

« Reply #6 on: 14 / January / 2008, 12:57:34 »

I don't exactly know how it's done, but it's doesn't look like memory-mapped hardware...

Quote

   p = 0x1163B8E0;
   if(dg++ == 10) *p = 0xDA;
   sprintf(osd_buf, "%02X", *p);
   draw_txt_string(3, 0, osd_buf);

that actually changes the value and it's persistent. Looks like normal memory to me and it can possibly be used for applications as long as they don't involve taking pictures

It's also not overwritten when I record a video. This all on my S5IS of course.
Anyway, this looks like either some task copies the stuff there or the hardware copies it there directly (DMA?). I don't really think it'd be possible to write there if it were the sensor itself.

Logged

kwf

72

Re: Available camera memory and processor speed

« Reply #7 on: 16 / January / 2008, 07:39:01 »

Quote from: GrAnd on 14 / January / 2008, 08:11:37

32Mb. At least the first 32Mb of memory is readable.
Also, there should be a buffer memory. Also there is a memory for RAW data.

32MB sounds good, if its possible to use this memory for programs... that would be nice.
Maybe the clock frequency is high enough. I have read speculations that it should be around 200Mhz, can someone confirm this? So 200Mhz + 32MB ram should be enough for a lot of programs. Nearly enough for a small PDA.

I just can't think of a useful program, that would be worth the effort to port it ...

Doom?

Logged

GrAnd

916
[A610, S3IS]

Re: Available camera memory and processor speed

« Reply #8 on: 16 / January / 2008, 07:45:48 »

You can use whole 32Mb only in the case if all original software is eliminated. So, a program should be self-efficient because no OS functions will be available.

Logged

CHDK Developer.

kwf

72

Re: Available camera memory and processor speed

« Reply #9 on: 16 / January / 2008, 08:36:27 »

Sure, if you really need the whole 32MB. But my guess would be that only a small part (a few MB) is really occupied by programs. Hopefully most of it are buffers, which are only needed when taking photos, videos etc.

Quote from: GrAnd on 16 / January / 2008, 07:45:48

You can use whole 32Mb only in the case if all original software is eliminated. So, a program should be self-efficient because no OS functions will be available.

Logged