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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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.
The first routine should convert the integer value aint to a floating point value. As an example, let’s choose the 16C74 A. If the processor context, upon return from the interrupt, is not left exactly progarmmation way you found it, all kinds of subtle bugs and even major ckurs crashes can and will occur.
This allows sections of code to execute without the possibility of being interrupted. Finally, the floating point number is converted back into an integer aint so that PicBasic Pro can use it again. If the PICmicro has 2K or less of code space, the registers are not saved. Since PicBasic Pro only works with integers, aszembleur result will always be an 8-bit integer no larger than the actual result.
BAS que vous trouver dans C: 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 uses a quarter-wave lookup table to find the result. A assembkeur interrupt handler is placed at location 4 in the PICmicro. Below is one example program that demonstrates the use of the libraries. Your interrupt handler must save and restore any used registers.
This will allow PBP to complete each statement more quickly and handle any pending interrupts. You cannot tell ptogrammation variables are in use by the library routines at any given time.
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. This disables all the individual interrupts but leaves the Global Interrupt Enable bit set. If it is off, an interrupt is pending so it vectors to the users interrupt handler. 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.
As an example, lets say that the PicBasic Pro program just started execution of a Pause when an interrupt occurs. Cosine starts with a value in binary radians, 0 toas opposed to the usual 0 to degrees.
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. ZIPmay be downloaded. What this does is send the program back to what it was doing before the interrupt occurred.
This interrupt handler is simply a Return.
The appropriate floating point routines Microchip’s AN are included in this zip. Some other statement must be placed in the loop for the interrupt check to happen. Un informaticien ne peut compter le nombre d’heures passer devant le zssembleur. If the program uses the form: This short subroutine checks the state of the Global Interrupt Enable bit.
The necessary PicBasic Pro source code to integrate either the bit or bit Microchip assembleyr point routines into your program, FP. While it is not that difficult, it is not obvious how to make this work properly. It does not immediately vector to your interrupt handler. Interrupts in Assembler Interrupts in assembly language are a little trickier.
If it takes too long to execute, the Watchdog Timer could timeout and really make a mess of things. While it seems a simple matter to save W in any RAM register, it is actually somewhat more complicated. If it is buffering characters from a serial port, many characters will be missed. This is called saving and restoring the processor context. Interrupts in assembly language are a little trickier. Lisez bien les explications en anglais plus bas.
asswmbleur If you don’t have their assembler, it also may be downloaded from their web site. Generally, floating point operations occur between 2 numbers, so a second integer bint should also be converted.
Also, several example programs are included.
This instructs the compiler to place the variable at a particular location in RAM. In this manner, if the save of W “punches through” to another bank, it will not progammation other data. You must restore these registers at the end of your assembler interrupt handler.