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):||22 February 2011|
|PDF File Size:||20.28 Mb|
|ePub File Size:||11.37 Mb|
|Price:||Free* [*Free Regsitration Required]|
While it seems a simple matter to save W in any RAM register, it is actually somewhat more complicated.
It could be up to 10 seconds later before the interrupt handler is executed. Sine starts with a value in binary radians, 0 toas opposed to the usual 0 to degrees.
This should ensure that it is in pjc first 2K to minimize boundary issues.
Therefore you must reserve a RAM register location in each bank of the device at the same offset. Keep in mind the interrupt flag is checked after each instruction. Un programmeur averti en vaut deux.
If it takes too long to execute, assembleuur Watchdog Timer could timeout and really make a mess of things.
Episode 1 : Programme d’une seule LED avec simulation sur ISIS – PIC 16F877
Goto loop ‘ Wait here till interrupted. Un informaticien ne peut compter le nombre d’heures passer devant le clavier. 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.
SQR returns the square root of a value. As an example, let’s choose the 16C74 A. Interrupts in Assembler Interrupts in assembly language are a little trickier. It uses a quarter-wave lookup table to find the result. ZIPmay be downloaded. BAS que vous trouver dans C: Label is the beginning of your interrupt routine. To be safe, we need to reserve the same location in each bank. The first routine should convert the integer value aint to a floating point value.
The appropriate floating point routines Microchip’s AN are included in this zip. 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.
Since PicBasic Pro only works with integers, the result will always be an 8-bit integer no larger than the actual result.
Your interrupt handler must save and restore any used registers. If it is buffering characters from a serial port, many characters will be missed.
You cannot tell which variables are in use by the library routines at any given time. You should create variables in the PicBasic Pro program for the express purpose of saving W, the STATUS register and any other register that may need to be altered by the interrupt handler. SIN returns the 8-bit sine of a value. It immediately jumps to the loop with no interrupt check.
These routines can be integrated into a PicBasic Pro program and called, if floating point is a necessity. While it is not that difficult, it is not obvious how to make this work properly. Programmwtion does not immediately vector to your interrupt handler. In this manner, if the save of W “punches through” to another bank, it will not corrupt other data.
Episode 1 : Programme d’une seule LED avec simulation sur ISIS – PIC 16F |
This will allow PBP to complete each statement more quickly and handle any pending interrupts. The necessary PicBasic Pro source code to integrate either the bit or bit Microchip floating point routines into your program, FP. If the program uses the form: If the PICmicro has 2K or less of code space, the registers are not saved. Some other statement must be placed in the loop for the interrupt check to happen. See the example below for a demonstration of this.
Cosine starts with a value in binary radians, 0 toas opposed to the usual 0 to degrees. Also, several example programs are included. This short subroutine checks the state of the Global Interrupt Enable bit. Generally, floating point operations occur between 2 numbers, so a second integer bint should also be converted. Lisez bien les explications en anglais plus bas.