| ??? 06/30/08 13:20 Read: times |
#156316 - more confusing terminology... Responding to: ???'s previous message |
Erik Malund said:
xdata is used for external memory. i am not using any external memory.
yes, you are, the RD2 has, get this "external memory internal to the chip". The first who did this was Intel itself, in the 80C51RA (and, later, RB and RC) chips (the "R" in the suffix stays supposedly for "RAM"). Intel coined the term "extended" ram, ERAM, for the "internal external memory", but it did not really stick. The RD2-s are successors to this early chip. Please note that there is usually a SFR bit (or a set of bits) which enable/disable some or whole of this "internal/external" RAM. Please read the relevant portions of the datasheet for the details. JW |
| Topic | Author | Date |
| P89C51RD2BN MEMORY MODEL | 01/01/70 00:00 | |
| look up the "code" keyword in the manual | 01/01/70 00:00 | |
| look up the "xdata" keyword in the manual | 01/01/70 00:00 | |
| the whole manual might be worth reading... ;-) | 01/01/70 00:00 | |
| look up the word "overflow" in a dictionary | 01/01/70 00:00 | |
| ??????????????? | 01/01/70 00:00 | |
| Explanation | 01/01/70 00:00 | |
| about the size of data memory | 01/01/70 00:00 | |
| Arrays | 01/01/70 00:00 | |
| is this caused by the model? | 01/01/70 00:00 | |
| Re: Little more information | 01/01/70 00:00 | |
| Problem Solved | 01/01/70 00:00 | |
| IDATA - beware | 01/01/70 00:00 | |
| why not XDATA | 01/01/70 00:00 | |
| external memory?????? | 01/01/70 00:00 | |
| yes, you are | 01/01/70 00:00 | |
more confusing terminology... | 01/01/70 00:00 |