| ??? 01/27/05 20:52 Read: times |
#85967 - 8051 RTOs Limitations/Issues/Opportunity Responding to: ???'s previous message |
Russell Bull said:
Ian, you do understand that a RTOS on a 8051 is a bit of a compromise due to the limited stack? Indeed, all the ones I have been able to find only work on variants with plenty of RAM or force you to use XRAM. Trying to fit enough stack for a number of tasks can be 'fun'. This is, unless the task switching is co-operative. I am trying to make a useful RTOS for 8051s with very limited resources - 128 bytes RAM, no Timer2 and small code space. If it works out OK I plan to release it free of charge. It is based on a cooperative scheduler described by Michael J Pont in his book Patterns for Time Triggered Embedded Systems. I am currently on target for the scheduler and despatcher to fit in less than 200 bytes of code and for 8 tasks to require just 24 bytes of RAM. Ian |
| Topic | Author | Date |
| Computed Call | 01/01/70 00:00 | |
| Computed Call | 01/01/70 00:00 | |
| simulate an LCALL @A+DPTR instruction? | 01/01/70 00:00 | |
| Solution | 01/01/70 00:00 | |
| Computed LCALL | 01/01/70 00:00 | |
| Computed LCALL | 01/01/70 00:00 | |
| Table offset | 01/01/70 00:00 | |
| x2, not x3 | 01/01/70 00:00 | |
| what is the problem | 01/01/70 00:00 | |
| My Problem | 01/01/70 00:00 | |
| never heard of it | 01/01/70 00:00 | |
| It is....... | 01/01/70 00:00 | |
| RTOS | 01/01/70 00:00 | |
| 8051 RTOs Limitations/Issues/Opportunity | 01/01/70 00:00 | |
| How? | 01/01/70 00:00 | |
| Decisions, decisions | 01/01/70 00:00 | |
| Small systems - task scheduling | 01/01/70 00:00 | |
| Worth it? | 01/01/70 00:00 | |
| Scheduler | 01/01/70 00:00 | |
| Scheduler | 01/01/70 00:00 | |
| running small in a big way | 01/01/70 00:00 | |
| Example | 01/01/70 00:00 | |
| in very small chips | 01/01/70 00:00 | |
| In all sorts of sizes of chips | 01/01/70 00:00 | |
| time dependednt | 01/01/70 00:00 | |
| RTOS or Not | 01/01/70 00:00 | |
| opinion piece | 01/01/70 00:00 | |
| fact piece | 01/01/70 00:00 | |
| Opinion piece | 01/01/70 00:00 | |
| suggestion piece | 01/01/70 00:00 | |
| reasons | 01/01/70 00:00 | |
| Polite discussion | 01/01/70 00:00 | |
| Politeness | 01/01/70 00:00 | |
| Thanks | 01/01/70 00:00 | |
| Politeness | 01/01/70 00:00 | |
| What are you Rabbiting on about? | 01/01/70 00:00 | |
| Close but no Cigar | 01/01/70 00:00 | |
| Rabbit food | 01/01/70 00:00 | |
| Plessey | 01/01/70 00:00 | |
| small world | 01/01/70 00:00 | |
Smaller than you imagine! | 01/01/70 00:00 | |
| I use the computed LCALL ... | 01/01/70 00:00 | |
| go it | 01/01/70 00:00 | |
| Call tabs in-line | 01/01/70 00:00 | |
| abbreviated | 01/01/70 00:00 | |
| ... and further optimized... | 01/01/70 00:00 | |
| has been already disscussed | 01/01/70 00:00 | |
| Scheduler of course | 01/01/70 00:00 | |
| Scheduler | 01/01/70 00:00 |