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.
|Published (Last):||16 October 2017|
|PDF File Size:||13.99 Mb|
|ePub File Size:||2.9 Mb|
|Price:||Free* [*Free Regsitration Required]|
If it takes too long to execute, the Watchdog Timer could timeout and really make a mess of things. Lisez bien les explications en anglais plus bas. You cannot tell which variables are in use by the library routines at any given time. Goto loop ‘ Wait here till interrupted. While it seems a programmatioon matter to save W in any RAM register, it is actually somewhat more complicated.
Which brings us the first issue. Label is the beginning of your interrupt routine. If you have reserved a location in Bank0 and the current register pointers are set to Bank1, for example, you could overwrite an unintended location. Below is one example program assebleur demonstrates the use of the libraries.
Episode 1 : Programme d’une seule LED avec simulation sur ISIS – PIC 16F |
This should ensure that it is in the first 2K to minimize boundary issues. It uses a quarter-wave lookup table to find the result. While it is not that difficult, progammation is not obvious how to make this work properly.
The appropriate floating point routines Microchip’s AN are included in this zip. See the example below for a demonstration of this. In this case we will choose the first location in each bank. This will allow PBP to complete each statement more quickly and handle any pending interrupts. Your interrupt handler must save provrammation restore any used registers.
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 was so rudely interrupted. 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.
If the PICmicro has 2K or less of code space, the registers are not saved.
Cosine starts with a value in binary radians, 0 toas opposed to the usual 0 to degrees. A short interrupt handler is placed at location 4 in the PICmicro. This instructs the compiler to place the variable at a particular location in RAM. SIN returns the 8-bit sine of a coyrs. Since PBP statements are not re-entrant PBP must finish the statement that is being executed before it can begin a new one there could be considerable delay latency before the interrupt is handled.
The best place to put the assembly language interrupt handler is probably at the very beginning of your PicBasic Pro program.
Episode 1 : Programme d’une seule LED avec simulation sur ISIS – PIC 16F877
Therefore you must reserve a RAM register location in each bank of the device at the same offset. Interrupts in Assembler Interrupts in assembly language are a little trickier. The interrupt routine should be as short and fast as you can possibly make it. The necessary PicBasic Pro source code to integrate either the bit or bit Microchip floating point routines into your program, FP.
All previous return addresses will be lost in this case. The first routine should convert the integer value aint to a floating point value.
Generally, floating point operations occur between assemblekr numbers, so a second integer bint should also be converted. If it is off, an interrupt is pending so it vectors to the users interrupt handler. Finally, you need to tell PBP that you are using an assembly language interrupt handler and where to find it. A special construct has been added to the VAR command to allow this: It does not immediately vector to your interrupt handler.
The problem occurs in that you have no way of knowing what register bank you are pointing to when the interrupt happens. 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.
This short subroutine checks the state of the Global Interrupt Cuors bit. Courx off this bit tells PBP an pfogrammation has happened and it will execute the interrupt handler forever. This interrupt handler is simply a Return. Un programmeur averti en vaut deux. SQR returns the square root of a value. Also, several example programs are included. As an example, lets say that courd PicBasic Pro program programmatiion started execution of a Pause when an interrupt occurs.
These routines can be integrated into a PicBasic Pro program and called, if floating point is a necessity. This disables all the individual interrupts but leaves the Global Interrupt Enable bit set. In this manner, if the save of W “punches through” to another bank, it will not corrupt other data.