Next Memory Bank Select
From SpecNext official Wiki
| Number | $DFFD |
|---|---|
| Decimal | |
| Short desc. | Provides additional bank select bits for extended memory. |
| Bit Mask | %1101 1111 1111 1101 |
| Readable | No |
| Writable | Yes |
| Subsystem | Memory map |
bits 3:0 = most significant bits of the 16K RAM bank selected in Memory Paging Control ($7FFD / 32765)
Port 0xDFFD bits 3:0 are combined as the highest bits with the bank selected in port 0x7FFD to form a 7-bit bank number.