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Work with a poorly documented chinese processor + several questions

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amyk:
Article about "opening" a slightly newer MTK processor, might be of help: https://www.bunniestudios.com/blog/?p=4297

soFPG:

--- Quote ---Article about "opening" a slightly newer MTK processor, might be of help
--- End quote ---
Thanks for your reply. I read the blog post two times and watched his talk at the conference but I wasn't able to pull much information out for me. Not much indepth detail in my opinion. Also wasn't able to find his GitHub...

So meanwhile what I found out is that the CH340G actually supports 2.8V as a minimum supply voltage (see attached picture).
I am still looking for a cheap SRAM with capacity >= 512kByte...

coppice:

--- Quote from: RoGeorge on November 03, 2019, 06:31:23 pm ---If you have the time and the will to spend it on reverse engineering, better look into some very widespread old mobile phone, like a Nokia 3310 or 5110, so once you manage to take control of it, you would have virtualy infinite free hardware to play with, or to re-purpose it for future projects.

The question is, why that old GSM board/processor?

--- End quote ---
There are enormous numbers of old phones based on the Mediatek chip sets. They are no better or worse documented than the TI chip sets in old Nokia phones. Both makers produced good documentation, but the documentation was only made available to verified customers. Some of the Mediatek documentation might only be in Chinese (probably both simplified and traditional, with Mediatek being a Taiwanese company, but most of their customers being in China). You might be able to be get hold of stray copies for either chip set, but its pot luck.

soFPG:
So this chip has a shared memory bus for SRAM and Flash. Besides address- and data lines there are also #UB and #LB pins which select either the upper or lower byte of the 16 bits of data.

I was able to find SRAM modules which also have these #UB and #LB pins but unfortunately I wasn't successful with flash modules (which makes sense - why would you want to split a cpu instruction?).

Anyone here who knows if I can just ignore #UB & #LB pins for the flash module?

A possible solution of course would be to use two 8-bit modules and then somehow combine #CS and #UB / #LB.

soFPG:
Found this tool which claims to be able to flash MT6205B CPU: http://mobisoft.com.ua/files/3113_china-tools-v1.03.html (this site in general is a pure gold)

Edit: Also a firmware for the MT6205B: http://mobisoft.com.ua/files/773_full-sky-mix-301-300-6205.html , but don't know what I can do with it

Edit_2: The schematic from a chinese phone with an MT6205B uses combined flash + sram IC AM41DL6408G: http://www.chipfind.ru/datasheet/amd/am41dl6408g.htm and according to the block diagram on page 5, #UB & #LB are only used for the SRAM, not for the flash! So that basically means that I can use any 16-bit flash and don't have to worry about #UB / #LB.

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