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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The PicBasic Pro programs must be compiled using the -ampasm switch to invoke Microchip’s assembler. Interrupts in assembly language are a little trickier. If you don’t have their assembler, it also may be downloaded from their web site.
BAS que vous trouver dans C: 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.
Since PicBasic Pro only works with integers, the result will always be an 8-bit integer no larger than the actual result. Also, several example programs are included. If it is buffering characters from a serial port, many characters will be missed. SQR returns the square root of a value. This instructs the compiler to place progrzmmation variable at a particular location in RAM.
Label is the beginning assembleu your interrupt routine. 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.
In this manner, if the save of W “punches through” to another bank, it will not corrupt other data. These routines can be integrated into a PicBasic Pro program and called, if floating point is a necessity.
It uses a quarter-wave lookup table to find assemmbleur result. 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. It immediately jumps to the loop with no interrupt check.
This short subroutine checks the state of the Global Interrupt Enable bit. Sine starts with a value in binary radians, 0 toas opposed to the usual 0 to degrees. 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. Your interrupt handler must save and restore any used registers.
Finally, the floating point number is converted back into an integer aint so that PicBasic Pro can use it again. SIN returns the 8-bit sine of a value. This disables all the individual interrupts but leaves the Global Interrupt Enable bit set. The problem occurs in that you have no way of knowing what register bank you are pointing to when the interrupt happens.
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. What this does is send the program back to what it was doing before the interrupt occurred. Interrupts in Assembler Interrupts in assembly language are a little trickier.
Courd necessary PicBasic Pro source code to integrate either the bit or bit Microchip floating point routines into your program, FP.
Circuit a microcontrôleurs (MCU)
progrqmmation The appropriate floating point cojrs Microchip’s AN are included in this zip. Ocurs an example, let’s choose the 16C74 A. All previous return addresses will be lost in this case. If it takes too long to execute, the Watchdog Timer could timeout and really make a mess of things. While it is not that difficult, it is not obvious how to make this work properly. The best place to put the assembly language interrupt handler is probably at the very beginning of your PicBasic Pro program.
You cannot tell which variables are in use by the library routines at any given time. A short interrupt handler is placed at location 4 in the PICmicro. Un informaticien ne peut compter le nombre d’heures passer devant le clavier. Turning couts this bit tells PBP an interrupt has happened and it will execute the interrupt handler forever. Which brings us the first issue. This should ensure that it is in the first 2K to minimize boundary issues.
To be safe, we need to reserve the same location in each bank.
Generally, floating point operations occur between 2 numbers, so a second integer bint should also be converted. Therefore you must reserve a RAM register location in each bank of the device at the same offset.
Cosine starts with a value in binary radians, 0 toas opposed to the usual 0 to degrees. Lisez bien les explications en anglais plus bas. It could be up to 10 seconds later before the interrupt handler is executed. The interrupt routine should be as short and fast as you can possibly make it. Finally, you need to tell PBP that you are using an assembly language interrupt handler and where to find it.