Medion MD85264 (AES2501 chip)
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* the device has remote wakeup feature.

WRITE:
 80 01 =
 80 04 =
 81 xx = read registers
 82 40 =
 b0 27 =
 b4 00 =
 ff 00 = reset?
 8e xx = ADC Gain?
 91 xx = ADC HiRef?
 92 xx = ADC LoRef?

READ:
 80..be + 1 byte	reg value
 ba + 1 byte            relative Y coordinate
 bc + 1 byte            relative Y coordinate
 f0 + 8 bytes		image data for one column, 16 pixels
 df + 8 bytes		?
 e0 + 192*8 bytes	image data for one strip, 16*192 pixels
 de + 16*2 bytes	histogram? little endian, 16*uint16_t, sum = 0x780 = 1920

image data format:
 - column-wise, 192 columns/strip, 16 pixels/col, 4 bits/pixel
 - the first byte contains the first two pixels, etc.
 - lower nibble comes first.
 - e.g. raw data = 00 01 02 03 04 05 06 07 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 ...
   decoded image:
        x -->
      y 0 8 0 ...
      | 0 1 2 ...
      v 1 9 1 ...
        0 1 2 ...
        2 a 2 ...
        0 1 2 ...
        3 b 3 ...
        0 1 2 ...
        4 c 4 ...
        0 1 2 ...
        5 d 5 ...
        0 1 2 ...
        6 e 6 ...
        0 1 2 ...
        7 f 7 ...
        0 1 2 ...
