Файл: Kit 81 Simple PICMicro programmer (2002).pdf

Pretty simple isn’t it.

Modify the flash.asm code then try it out and see.

How can you convert this code into a single instruction??

movlw b'00000000' movwf PORTB

Check out the data sheet to find out and look in the instructions section.

(Hint: the instruction is cl.. PORTB)

If you are stuck, turn the page....

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clrf PORTB

For some additional exercises.....

Try to make the LEDs count up in binary. Try to make LEDs count down in binary.

Try to makes the LEDs come on one at a time moving from left to right.

There are code examples for these exercises in the installation directory for you to look at. Try to do them yourself and use the examples if you get confused.

binaryup.asm

binarydn.asm

binarylr.asm

Two of these programs use the XORLW instruction to make sure the data written to PORTB is correct. Try to figure out why it was used.

XOR TRUTH TABLE

Hint: Notice how A XOR 1 = opposite A

If XORLW wasn’t used how would you increment or decrement the Counter value to make the program work. As you will find out, it’s much better to use the XOR instruction.

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CONFIG

The __CONFIG statement at the start of the code is used to control the

Configuration Fuse register. This is a special location that controls how the chip operates. Things like Oscillator Type, Watch Dog Timer, Programming Mode and other features. These are listed in the data sheets. The value used...

__CONFIG 0x3FFB

... is a specially selected value for this project. It selects RC Oscillator, Watch Dog Disabled and no Code Protection.

RC mode was selected because the PIC clock source connected to the demonstration socket is a simple Resistor/Capacitor circuit.

Please do not alter this value as the PIC may stop operating when you run the code. If you accidently changed the value, change it back and reassemble. After programming again, the chip should run normally.

Cheers and happy programming.

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PARTS LIST

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