Datasheet

PICkit™ 3 Debug Express

Headers for the libraries can be found in the MCC18 header directory C:\MCC18\h.

The source code for most of the libraries can be found in C:\MCC18\src, and the

libraries themselves are in C:\MCC18\lib. For more detailed information on the

included library functions see the “MPLAB C18 C Compiler Libraries” document

(DS51297).

The other new line of special interest is a function call to a function in the delays library:

Delay1KTCYx(50);

This function creates a time delay with a software of 1000 (1k) instruction cycles (TCY)

times the argument value. In this case, the argument is 50 so this function will delay for

50 x 1,000 = 50,000 instruction cycles. The instruction rate on PIC18FXXXX

microcontrollers is equal to 1/4

the oscillator clock; in other words, it takes 4 clocks to

execute an instruction. In this case the clock is the internal oscillator at 1 MHz, so the

instruction rate is 250 kHz, or TCY = 4us per instruction. The total delay is 50,000 x 4us

= 200 ms, which is slow enough for the human eye to see the LED turning on and off.

The Lesson 2 program runs this delay inside an indefinite while loop, which sets the

RD7 I/O pin to the complement of its current value (the effect is to switch it back and

forth between high and low) with a 200 ms delay in between each RD7 output level

change. This blinks the demo board LED 7.

3.2.4 Build and Program the Lesson 2 Code

Select MPLAB IDE menu, build the Lesson 2 project and program the code into the

demo board PIC18F45K20 using the PICkit 3 Programmer as we did in Lesson 1.

The demo board LED 7 will blink continuously at 200 ms on and 200 ms off.