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Quote Originally Posted by PicBasic Pro Compiler manual
For compatibility with the BASIC Stamp, pins used in PicBasic Pro Compiler commands may also be referred to by a number, 0 - 15. This number references different physical pins on the PICmicro MCU hardware ports dependent on how many pins the microcontroller has.

If a port does not have 8 pins, such as PORTA, only the pin numbers that exist may be used, i.e. 8 - 12. Using pin numbers 13 - 15 will have no discernable effect.

This pin number, 0 - 15, has nothing to do with the physical pin number of a PICmicro MCU. Depending on the particular PICmicro MCU, pin number 0 could be physical pin 6, 21 or 33, but in each case it maps to PORTB.0 (or GPIO.0 for 8-pin devices, or PORTC.0 for a PIC14000).
-Adam-