Layer 2 Access Port
From SpecNext Wiki
| Number | PortNumber::$123B |
|---|---|
| Decimal | NumberDec:: |
| Short desc. | [[ShortDesc::Enables Layer 2 and controls paging of layer 2 screen into lower memory.]] |
| Bit Mask | [[PortMask::%0001 0010 0011 1011 ??]] |
| Readable | Readable::Yes |
| Writable | Writable::Yes |
| Subsystem | Subsystem::Layer 2 |
| Bit | Description |
|---|---|
| 7-6 | Video RAM bank select (write/read paging) |
| 5-4 | Reserved, write 0 |
| 3 | Use Shadow Layer 2 for paging - {{#ask:
TBRegisterNumber::$13 }} ($13) |
| 2 | Enable Layer 2 read-only paging |
| 1 | Layer 2 visible - {{#ask:
TBRegisterNumber::$12 }} ($12) Since core 3.0 this bit has mirror in {{#ask: TBRegisterNumber::$69 }} ($69) |
| 0 | Enable Layer 2 write-only paging |