===== DIGIC 8 Register Map: =====

==== UART ====

Controls physical UART connection.

^ Address        ^ Description     ^
| ''0xD01202F0'' | UART1_RX_SELECT_CONFIG |
| ''0xD01202F4'' | UART1_TX_SELECT_CONFIG |
| ''0xD01302F0'' | UART1_RX_SELECT_MASK   |
| ''0xD01302F4'' | UART1_TX_SELECT_MASK   |


''UART'' is connected to physical ICU UART on external debug connector. Handled by ''uart_change'' command on drysh.

''0x0'' selects ICU (DryOS on ARM core), ''0x2'' for CCLIME (DryOS on Xtensa core, network).

==== Display ====

^ Address        ^ Description   ^
| ''0xD030422C'' | ??            |
| ''0xD0304230'' | VRAM pointer  |
| ''0xD0304234'' | VRAM pitch    |
| ''0xD0304238'' | Resolution    |
| ''0xD030423C'' | ??            |
==== LV peaking (Highlights / zebra) ====

^ Address        ^ Output  ^ Type      ^ Controls what?      ^
| ''0xD0300520'' | HDMI    | zebra     | enable / disable    |
| ''0xD0300750'' | HDMI    | overexpo  | threshold and style |
| ''0xD0300754'' | HDMI    | overexpo  | color               |
| ''0xD0300758'' | HDMI    | underexpo | threshold and style |
| ''0xD030075C'' | HDMI    | underexpo | color               |
| ''0xD0304220'' | LCD/EVF | zebra     | enable / disable    |
| ''0xD0304488'' | LCD/EVF | overexpo  | threshold and style |
| ''0xD030448C'' | LCD/EVF | overexpo  | color               |
| ''0xD0304490'' | LCD/EVF | underexpo | threshold and style |
| ''0xD0304494'' | LCD/EVF | underexpo | color               |

Registers used by ''DispVram'' State object to control overexposure highlighting feature.

Different addresses and slightly different values than Digic 6/7, but capabilities are very similar.

__It is possible to have independent zebras configured on LCD and HDMI while running in Clean HDMI mode!__

===Note on directly writing the registers===
Directly writing some registers doesn't work (values are overridden). On R170.739 that happens for HDMI enable register, but this seems to differ from model to model. See [[digic6:registers|DIGIC 6 Register Map:]] for more info.

TL;DR is that you need to find (via xrefs / static code analysis) where reg value is stored, and update that memory address instead.

===Enable register===

''reg & 0x100'' controls if highlight is enabled or not.

Value written should be masked ''0x100'' with one read from ''reg + 0x2000''

This register lies in **Display registers** range and most likely has more meanings.

===Threshold / style register===

<code>
**** **** **** **** **** **** **** ****
*... .... .... .... .... .... .... .... visibility (on/off)
..** .... .... .... .... .... .... .... stripes move speed (0-3)
.... ...* .... .... .... .... .... .... stripes angle (45 / -45 deg)
.... .... ..** .... .... .... .... .... stripes style
.... .... .... .*** .... .... .... .... stripes opacity
.... .... .... .... **** **** .... .... threshold (underexpo)
.... .... .... .... .... .... **** **** threshold (overexpo)
</code>

Value written should be masked ''0xB137FFFF'' with one read from ''reg + 0x2000''

^ Field        ^ Range ^ Description ^
| visibility   | 0,1   | zebra visibility (do not confuse with Enable register)  |
| speed        | 0-3   | lines/dots are moving slower -> faster                  |
| angle        | 0-1   | 0: 45 deg, 1: -45 deg                                   |
| style        | 0-2   | 0: light dots, 1: thin lines, 2: thick lines            |
| opacity      | 0-7   | very opaque -> solid color                              |
| underexpo_th | 0-255 | Threshold on undexexpo register, ignored on overexpo    | 
| overexpo_th  | 0-255 | Threshold on overexpo register, ignored on underexpo    |

**Note: On HDMI max threshold is 0xE8** Values above that are not displayed!

===Color register===

Controls color of highlight overlays. ''??YYUUVV'' format. Canon code defaults to black (''00008080'')

===More registers===

Code suggests there are more registers:

^ Output ^ Reg       ^ Addresses                 ^ Range   ^
| HDMI   | Enable    | ''0xD0300520 + 0x30 * n'' | n∈⟨0,7⟩ |
| LCD    | Enable    | ''0xD0304220 + 0x30 * n'' | n∈⟨0,7⟩ |
| HDMI   | Threshold | ''0xD0300750 + 0x8  * m'' | m∈⟨0,5⟩ |
| HDMI   | Color     | ''0xD0300754 + 0x8  * m'' | m∈⟨0,5⟩ |
| LCD    | Threshold | ''0xD0304488 + 0x8  * m'' | m∈⟨0,5⟩ |
| LCD    | Color     | ''0xD030448C + 0x8  * m'' | m∈⟨0,5⟩ |

n values above 0 and m values above 1 are not understood. There's no visible difference on screen.

For ''m > 1'' Threshold registers accept both under and overexposure thresholds at the same time, but since those have no visible effects on displayed image - meaning is unknown.

Guess: maybe ''m > 1'' are in use for 10 bit / HDR mode?
==== Audio ====

^ Address         ^ Description                     ^
| ''0xD800021D '' | Left Microphone Level and Peak  |
| ''0xD8000220 '' | Right Microphone Level and Peak |