libopencm3
A free/libre/open-source firmware library for various ARM Cortex-M3 microcontrollers.
LPC13
Here is a list of all modules:
[detail level 12]
 LPC13xxLibraries for NXP Semiconductors LPC13xx series
 GPIOlibopencm3 LPC13xx General Purpose I/O
 LPC13xx DefinesDefined Constants and Types for the LPC13xx series
 GPIO DefinesDefined Constants and Types for the LPC13xx General Purpose I/O
 User interrupt service routines (ISR) prototypes for LPC 13xx series
 DebuggingMacros and functions to aid in debugging
 NVIC Defineslibopencm3 Cortex Nested Vectored Interrupt Controller
 User interrupts for LPC 13xx series
 Cortex M0/M3/M4 System InterruptsIRQ numbers -3 and -6 to -9 are reserved
 SysTick Defineslibopencm3 Defined Constants and Types for the Cortex SysTick
 Clock source selection
 User interrupt service routines (ISR) defaults for LPC 13xx series
 NVIClibopencm3 Cortex Nested Vectored Interrupt Controller
 SysTicklibopencm3 Cortex System Tick Timer