Canon 850D / T8i

Started by names_are_hard, November 26, 2021, 04:28:37 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

names_are_hard

I was taken by a fey mood, and have produced this:



This was my first time porting to Digic 8, and it's a bit different from the existing Digic 8 cams I've looked at.  There's a very important change to early boot process that was hard to determine, initialising the second core has changed.  Everything else seems normal enough so far, Kitor helped with the Ximr stuff, it seems to be closest to RP.

Dumped the roms with Basic.  Works well enough in Qemu to test the very early code, although Qemu will need updating due to the boot process change, MMIO addresses are used differently and Qemu assumes all D8 will be the same.  I haven't tried UART yet but the connector is under the thumb grip as is common on modern cams.

I don't recommend anyone try to run this yet, but the source may be useful for people looking at other D8 cams: https://github.com/reticulatedpines/magiclantern_simplified/commits/850d_initial_stubs

Buttons aren't mapped yet, graphics don't display how I'd expect, etc, lots of other bugs I'm sure.  I'll try to improve it to the same state as 200D.

names_are_hard

Got some features working (also on 200d).

Shutter count zero appears accurate for 850d:


Benchmarks and screenshots work (not all benchmarks tested):

Wlad81

Was the card reader overclocked?
Canon EOS 5D Mk III + Canon 24-105 F/4 L IS USM + SanDisk Exreme Pro 64 GB (SD, ML Nightly.2021Feb07.5D3113) + SanDisk Extreme Pro 128 GB (CF).

kitor

No, it does UHS-I natively.
Too many Canon cameras.
If you have a dead R, RP, 250D mainboard (e.g. after camera repair) and want to donate for experiments, I'll cover shipping costs.

Walter Schulz

Quote from: Wlad81 on January 02, 2022, 11:14:50 PM
Was card reader overclocked?

Measurements by https://cameramemoryspeed.com show that SD-card equipped cameras with Digic 6 and up support 104 MByte/s UHS-I transfer mode and numbers between 50 and 100 MByte/s should be expected without overclocking.

Wlad81

Great. I wonder, what speed would it give with overclocking.
Canon EOS 5D Mk III + Canon 24-105 F/4 L IS USM + SanDisk Exreme Pro 64 GB (SD, ML Nightly.2021Feb07.5D3113) + SanDisk Extreme Pro 128 GB (CF).

kitor

You know that OC right now is specific to Digic 5 models, right?

And it is "overclocking" controller to force it to use higher data modes (UHS-I modes on "regular" controller).

In case of Digic 8 it already has UHS-I and UHS-II support. If model does not support UHS-II it is a hardware limit - UHS-II mode requires additional connections between card and a host (second row of contacts).
Some UHS-II Digic 8 benchmarks area in EOS R thread
Too many Canon cameras.
If you have a dead R, RP, 250D mainboard (e.g. after camera repair) and want to donate for experiments, I'll cover shipping costs.