B0 to B13 are Byte variables (8 bits), and W0 to W6 are Word variables (16 bits).

The RAM available to the programmer of the '08 is 14 Bytes, or 7 Words, or a combination of these. Note that the Word variables and the Byte variables are overlaid, so writing a word to, say, W 4, results in variable B 8 & B 9 being occupied by the upper and lower bytes of the Word variable.

Also, the first Word (W0) is accessable as 16 bits of bit-memory, with the first Byte (B0) split into the first 8 Bits (BIT0, BIT1, BIT2, BIT3, BIT4, BIT5, BIT6, BIT7) and the next Byte (B1) split into the final 8 bits (BIT8 to BIT15).

W0

B0

B1

BIT7

BIT6

BIT5

BIT4

BIT3

BIT2

BIT1

BIT0

BIT15

BIT14

BIT13

BIT12

BIT11

BIT10

BIT9

BIT8

the use of the keyword symbol is a good idea...

Example code:

Let b0 = 3          'assigns the value of 3 to the variable b0  
Let b0 = b0 + 1     'adds 1 to the value stored in b0
debug b0            'shows the value of the variables

Now lets show a few more things...

Let b0 = 0 'assigns the value of 0 to the variable b0 repeat: 'this is a label that 'bookmarks' this spot in the program Let b0 = b0 + 1 'adds 1 to the value stored in b0 debug b0 'shows the value of the variables pause 1000 'pause for 1 second (1000 milliseconds) goto repeat 'this jumps to the label called repeat

In this example we assign a value of 0 to the variable b0, then repeatedly add 1 to it, displaying the results then pausing a second before repeating everything except the first line.

Interrupts