The pin arguments for the hal_LPC17xx_gpio_xxx() functions you describe are likely provided by a macro, of which I don't know the name. It may be in the var_io.h file for your eCos distribution.
Once you know the value of the PIN argument, you can call the hal_LPC17XX_gpio_xxx() functions of your distribution. -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
