| ??? 08/24/09 11:50 Read: times |
#168506 - Addressing bit memory indirectly |
Hi, I'm using an 8051 and trying to write a program using assembly language. Everything I've read says that bit memory is directly addressable and can be manipulated with setb and clr. What I want to do is something like "JB @R0,CHANGE" where R0 holds the address of the bit. My compiler doesn't seem to like this language though. Am I missing something? The developers guide doesn't seem to say whether or not this is possible or give any examples of that usage. Does anyone have any insight?
By the way. the project is a MIDI keyboard controller. My plan is to have the 8051 poll the keyboard by putting a note number in R0 and on P1. Two chips, sn74ls138n and sn74ls151n will decipher this number and poll one key at a time and send the result to P3.7. It is the value of P3.7 that I want to store in bit RAM at the same address as the note number so that the controller will only send a MIDI message if the note has changed state from the last time it was polled. Then increment R0 (next note)and start again. |
| Topic | Author | Date |
| Addressing bit memory indirectly | 01/01/70 00:00 | |
| Not possible. | 01/01/70 00:00 | |
| so why Bit addressable memory? | 01/01/70 00:00 | |
| sure you can and THINK | 01/01/70 00:00 | |
| Fast and saves code and RAM space | 01/01/70 00:00 | |
| No such instruction... | 01/01/70 00:00 | |
| Thanks so much | 01/01/70 00:00 | |
| That's _too_ limited... | 01/01/70 00:00 | |
| Not vast - actually quite small. | 01/01/70 00:00 | |
| bible time | 01/01/70 00:00 | |
| store bit address... | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| if '2051' is the Atmel, then | 01/01/70 00:00 | |
| "cable" only for the "S" | 01/01/70 00:00 | |
| I second the motion and add | 01/01/70 00:00 | |
| I have... | 01/01/70 00:00 | |
| Smoking bad for the health | 01/01/70 00:00 | |
| an issue many newbies are not aware of is ... | 01/01/70 00:00 | |
| NXP??? | 01/01/70 00:00 | |
| Design flaw? | 01/01/70 00:00 | |
| a feature | 01/01/70 00:00 | |
| cheap | 01/01/70 00:00 | |
Code: Addressing bit memory indirectly | 01/01/70 00:00 |