| ??? 10/12/06 06:06 Read: times |
#126266 - datasheet says Responding to: ???'s previous message |
hi,
Toto Lotto said:
I know that using the EXTRAM bit, the access between internal or external memory can be changed.
So what is the real purpose of the XRS-bits. From pages 24-25: The bits XRS0 and XRS1 are used to hide a part of the available XRAM (which is physically located on-chip). Does the controler access external xram if the location is outside of the XRS-bits descripted internal xram range, even when EXTRAM bit cleared?
From pages 25: With EXTRAM=0 ... [skiped] ... An access to external data memory locations highter than the accessable size of the XRAM will be performed with the MOVX DPTR instructions in the same way as in the standard 80C51 with P0 and P2 as data/address busses, and P3.6 and P3.7 as write and read timings signals.So what is not clean here? Regards, Oleg |
| Topic | Author | Date |
| AT89C51ED2 XRS bits in AUXR | 01/01/70 00:00 | |
| internal external and the bits... | 01/01/70 00:00 | |
| Don't really understand | 01/01/70 00:00 | |
| Doesn't really understand | 01/01/70 00:00 | |
datasheet says | 01/01/70 00:00 |