| ??? 06/12/07 06:44 Read: times |
#140570 - Summary Responding to: ???'s previous message |
CODE is the only space from which the 8051 Architecure can fetch executable instructions;
CODE space is read-only; the 8051 Architecure has no instruction to write to CODE space. The various data spaces (DATA, IDATA, XDATA, PDATA) all have read and write access, but the 8051 Architecure cannot execute instructions from these spaces. The MOVC instruction allows code space to be read as data (not written, not executed). Richard Erlacher said:
Modern variants on this architecture sometimes, in some cases, violate these general rules. I don't think they actually violate these rules? What they do is to provide cunning schemes whereby the physical memory can be re-mapped to the CODE address space (where it can be executed) or to a data address space (where it can be read & written)... |
| Topic | Author | Date |
| 8051 ram space | 01/01/70 00:00 | |
| Yes | 01/01/70 00:00 | |
| Summary | 01/01/70 00:00 | |
| one example | 01/01/70 00:00 | |
| Yes, some of them do that ... | 01/01/70 00:00 | |
| DMA to internal XRAM? | 01/01/70 00:00 | |
I know that ... but it would be convenient ... | 01/01/70 00:00 |