| ??? 02/15/08 14:29 Read: times |
#150871 - Need help with RAM access via 8051 |
Hello all!
I am just learning 8051 and need some help: I have some values stored at ROM: DSEG AT 0 REG_0 :DS 1 REG_1 :DS 1 REG_2 :DS 1 REG_3 :DS 1 REG_4 :DS 1 REG_5 :DS 1 REG_6 :DS 1 REG_7 :DS 1 vec_name :DS 1 len :DS 1 vecr :DS 12 vecr = 12 numbers that represent offset for RAM. XSEG AT 0FF00H checks :DS 16 h :DS 1 m :DS 1 PositionN :DS 12 Now, what I am trying to do is to put a value at PositionN + vecr, i.e. if first number in vecr is 5; and PositionN locations is FF18, the value should be placed at FF18 + 5 in RAM. For now i have this code:
MOV DPTR,#PositionN
MOV A,#0FFH
MOVX @DPTR,A
How Can I add the offset to DPTR? Thank |
| Topic | Author | Date |
| Need help with RAM access via 8051 | 01/01/70 00:00 | |
| re | 01/01/70 00:00 | |
| RE: | 01/01/70 00:00 | |
| no need to put constant into dptr | 01/01/70 00:00 | |
| How can I get the low and high parts? | 01/01/70 00:00 | |
| what '51 assembler do you use? | 01/01/70 00:00 | |
| push/pop A | 01/01/70 00:00 | |
| In my asm push ACC works! | 01/01/70 00:00 | |
| Another question: | 01/01/70 00:00 | |
| options: | 01/01/70 00:00 | |
| By inc I mean increase the value in RAM by 1 | 01/01/70 00:00 | |
once DPTR points to that value... | 01/01/70 00:00 | |
| this is why it's dangerous... | 01/01/70 00:00 | |
| You can push/pop [direct] though. | 01/01/70 00:00 | |
| this is certainly correct... | 01/01/70 00:00 |