MTX Registers
These registers are responsible for controlling how framebuffer data can be DMA'd from the DS GPU, and also for configuring the upscaling matrix.
Registers
The physical address can be calculated by subtracting 0xEB00000 from the virtual address.
Control
| VAddress | Name | Width |
|---|---|---|
| 0x1EC1x000 | MTX_CNT | 4 |
| 0x1EC1x004 | MTX_SIZE | 4 |
| 0x1EC1x008 | ??? | 4 |
| 0x1EC1x00C | ??? | 4 |
| 0x1EC1x020 | ??? | 4 |
Matrix unit
There are two matrix units, one at +0x200, and the other one at +0x300
| VAddress | Name | Width | Description |
|---|---|---|---|
| 0x1EC1xn00 | KRN_WIDTH | 4 | Kernel width - 1 is written here, 1 <= width <= 8 |
| 0x1EC1xn04 | KRN_PATTERN_BITS | 4 | If the corresponding bit is set then a new pixel is read(?)
This value is 6 bits, but it has to be written with a 32bit write. |
| 0x1EC1xn40 | KRN_MTX | 0xC0 | int kerneldata[6][8]; - matrix data is written here, height is always 6 |
Descriptions
MTX_CNT
| Bit(s) | Description |
|---|---|
| 0 | Enable bit |
| 1 | ??? set after init sequence |
| 2 | ??? set after init sequence |
| 8-9 | Mode? 0 = 4byte color, 1 = 3byte color, 2 = 2byte color, 3 = 2byte color |
| 10-11 | Another mode? Input mode? Initialized to 0 |
| 12 | ??? initialized to 0 |
| 15 | ??? set after init sequence |
| 16 | ??? not yet inited bit ??? |
MTX_SIZE
| Bit(s) | Description |
|---|---|
| 0-8 | Output framebuffer width - 1 is written here |
| 16-25 | Output framebuffer height - 1 is written here |