Extraits de la documentation technique Microchip du PIC 16F Savoir concevoir et écrire un programme assembleur. cours sur les interruptions IF3. PiKdev, An IDE for the development of PIC based . http:// Cours de programmation. Lors de l’écriture d’un programme en assembleur 68HC11, une directive d’ assemblage Figure 6: Logiciel PCBUG11 en cours d’utilisation.
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While it seems a simple matter to save W in any RAM register, it is actually somewhat more complicated. As an example, let’s choose the 16C74 A.
Generally, floating point operations occur between 2 numbers, so a second integer bint should also be pi. In this manner, if the save of W “punches through” to another bank, it will not corrupt other data. It does not immediately vector to your interrupt handler.
A special construct has been added to the VAR command to allow this: Finally, you need to tell PBP that you are using an assembly language interrupt handler and where to find it. Label is the beginning of your interrupt routine. Since PicBasic Pro only works with integers, the result will always be an 8-bit integer no larger than the actual result.
Circuit a microcontrôleurs (MCU)
The readme files included in the zip explain the procedures in more detail. Interrupts in Assembler Interrupts in assembly language are a little trickier.
Goto loop ‘ Wait here till interrupted. The interrupt routine should be as short and fast as you can possibly make it. Lisez bien les explications en anglais plus bas. If it is buffering characters from a serial port, many characters will be missed.
Finally, the floating point number is converted back into an integer aint so that PicBasic Pro can use it again. Which brings us the first issue. If it takes too long to execute, the Watchdog Timer could timeout and really make a mess of things. If the program uses the form: This will allow PBP to assembbleur each statement more quickly and handle any pending interrupts. What this does is send the program back to what it was doing before the interrupt occurred.
You must restore these registers at the end of your assembler interrupt handler.
The first routine should convert the integer value aint to a floating point value. ZIPmay be downloaded.
Keep in mind the interrupt flag is checked after each instruction. The best place to put the assembly language interrupt handler prograjmation probably at the very beginning of your PicBasic Pro program.
As an example, lets say that the PicBasic Pro program just started execution of a Pause when an interrupt occurs.
You cannot tell which variables are in use by the library routines at any given time. This should ensure that it is in the first 2K to minimize boundary issues. The routine should end with an Retfie instruction to return from the interrupt and allow the processor to pick up where it left off in your PicBasic Pro program.
Un informaticien ne peut compter le nombre d’heures passer devant le clavier. The appropriate floating point routines Microchip’s AN are included in this zip.
This interrupt handler is simply a Return. It could be up to 10 seconds later before the interrupt handler is executed. Turning off this bit tells PBP an interrupt has happened and it will execute the interrupt handler forever.
Circuit a microcontrôleurs (MCU)
If the processor context, upon return from the interrupt, is not left exactly the way you found it, all kinds of subtle bugs and even major system crashes can and will occur. This short subroutine checks the state of the Global Interrupt Enable bit.
Also, several example programs are included. If it is off, an interrupt is pending so it vectors to the users interrupt handler. Using Microchip’s Floating Point Routines with PicBasic Pro Microchip has developed several different floating point routines in assembler and placed them on their web site. See the example below for a demonstration of this.
If the PICmicro has 2K or less of code space, the registers are not saved. If you need to alter any of these, and you probably will, you must save the current values so that you can restore them before allowing the processor to go back to what it was doing before it clurs so rudely interrupted.