This application blinks a static string on a development board LED, using a delay loop for timing. As previously discussed in the slow timer exampledelay loops are a rather horrible way to do timing if you have any concern for power consumption; therefore, a future example will show how to convert the delay loop to a hardware timer with deep sleep between state changes. Please refer to the encoding description to understand how the decode works. Details not relevant to the encoding and delay operationst are left out of this article, so the source or other examples on this site, as they are filled in should be consulted to clear these up.
As mentioned above, each line is processed at a speed of 1 microseconds for a 4 MHz crystal oscillator. If there is no delay subroutine, the time between RB0 being high and then low would just be 1 microsecond!
The LED blinking will be too fast to see in real time. If the COUNT1 is still not zero, the program will process the loop as indicated by the "goto loop1" instruction. The other possible value here is "0" which will place the result of the decrement to the W register. This is the default value of unused registers.
This means the loop will continue for instruction cycles! All in all, the routine would take x instruction cycles to process. This is equivalent to 65 ms of waiting time.
Point the label START as the first line in the program lines 3 and 4 Register COUNT1 and COUNT2 as variables for the delay subroutine 8 to 11 Go to bank 1 and set RB0 as output and then go back to bank 0 lines 16 to 19 Set RB0, wait for 65 ms with the help of the delay subroutine in lines 22 to 23 and then clear it then wait for 65 ms again lines 24 to 25 Go back to the portion of the program with label "main", effectively looping the code endlessly line 26 Start of delay subroutine line 28 End of program line 35 That's it!
I suggest you try the above code and use the circuit provided on this article. Have fun coding in PIC assembly language!Feb 08, · This tutorial video describe the procedure for calculating the required delay in assembly language for microcontroller for online delay calculation v.
If and Loop Statements in MIPS Branch Instructions In the MIPS assembly language, there are only two types of conditional branch instructions. This means you don’t have to remember any great variety of special case branching.
Where assembly code can be worthwhile might be in the middle of tight loops that are executed a lot, and which you don't expect to change any time soon. The above is a tight loop, but in this case the optimization would be to not loop at all.
MSP Example: Morse Code Blinker with Delay Loop. we can write a delay loop function, which delays for a specified period of time: see the excellent book The C Programming Language.
In this case, we delay for a dah length if the bit is set, and a dit length if the bit is clear. CHAPTER #2- CALL, LOOP AND JUMP INSTRUCTION IN In the sequence of instructions to be executed, it is often necessary to transfer program control to a different location.
There are many instructions in the to achieve this goal. This chapter covers the control transfer instructions available in Assembly Language.
The first operand in all the cases could be either in register or in memory. The second operand could be either in register/memory or an immediate (constant) value.
However, memory-to-memory operations are not possible.
These instructions compare or match bits of the operands and set the CF, OF, PF.