help me to understand 3 lines of code ( concerning assembly and PBP programming)

[ScaleRobotics]

This should get you started. Let us know if you have more questions after reading about them.

http://www.picbasic.co.uk/forum/show...9219#post89219

L?CALL _DoUSBOut ; is a call to subroutine _DoUSBOut

For your last question,
It looks like version 2.60a has included the register UCFG, so you should hopefully be ok adding the second line only,

UCFG = %00010100

From the data sheet:
Bit 4 means
1 = On-chip pull-up enabled (pull-up on D+ with FSEN = 1 or D- with FSEN = 0)

Bit 2 means :
1 = Full-speed device: controls transceiver edge rates; requires input clock at 48 MHz