Here is a list of all modules:

[detail level 1234]

▼CM3 Defines	Defined Constants and Types for Cortex M3 core features
Debugging	Macros and functions to aid in debugging
▼Cortex Core Defines	libopencm3 Defined Constants and Types for the Cortex Core
Cortex Core Atomic support Defines	Atomic operation support
Cortex-M Data Watch and Trace unit.	System Control Space (SCS) => Data Watchpoint and Trace (DWT)
Cortex-M Flash Patch and Breakpoint (FPB) unit
Cortex-M Instrumentation Trace Macrocell (ITM)
▼Cortex-M MPU Defines	libopencm3 Cortex Memory Protection Unit
MPU Registers
MPU TYPE register fields	The MPU_TYPE register is always available, even if the MPU is not implemented
MPU CTRL register fields	Defines for the Control Register
MPU RNR register fields	Defines for the Region Number Register
MPU RBAR register fields	Defines for the Region Base Address Register
▼MPU RASR register fields	Defines for the Region Attribute and Size Register
MPU RASR Attributes	Not all attributes are available on v6m
▼Cortex-M NVIC Defines	libopencm3 Cortex Nested Vectored Interrupt Controller
NVIC Registers
Cortex M0/M3/M4 System Interrupts	IRQ numbers -3 and -6 to -9 are reserved
User interrupts for Nordic Semi NRF51 series
▼Cortex-M System Control Block	The System Control Block is a section of the System Control Space
SCB Registers
SCB_CPUID Values
SCB_ICSR Values
SCB_VTOR Values
SCB_AICR Values
SCB_SCR Values
SCB_CCR Values
▼Cortex-M System Control Space	The System Control Space (SCS) is a memory-mapped 4KB address space that provides 32-bit registers for configuration, status reporting and control
SCS Registers
▼Cortex-M SysTick Defines	libopencm3 Defined Constants and Types for the Cortex SysTick
▼STK_CSR Values
Clock source selection
STK_RVR Values
STK_CALIB Values
Cortex-M Trace Port Interface Unit (TPIU)
▼Cortex Core Peripheral APIs	APIs for Cortex Core peripherals
DWT	libopencm3 Cortex-M Data Watchpoint and Trace unit
NVIC	libopencm3 Cortex Nested Vectored Interrupt Controller
SCB	libopencm3 Cortex-M System Control Block
SysTick	libopencm3 Cortex System Tick Timer
Coresight Registers	CoreSight Lock Status Registers and Lock Access Registers are documented for the DWT, ITM, FPB and TPIU peripherals
▼Peripheral APIs	APIs for device peripherals
CLOCK peripheral API	Access functions for the NRF51 Clock Controller
GPIO peripheral API	Access functions for the I/O Controller
I2C peripheral API	Access functions for the I2C Controller
PPI peripheral API	Access functions for the Programmable Peripheral Interconnect
RADIO peripheral API	Access functions for the 2.4 GHz Radio
RTC peripheral API	Access functions for the Real Time Counter Controller
TIMER peripheral API	Access functions for the Timer/Counter
UART peripheral API	Access functions for the UART controller
NRF51xx	Libraries for Nordic Semiconductor NRF51xx series
▼NRF51xx Defines	Defined Constants and Types for the NRF51xx series
CLOCK Defines	Defined Constants and Types for the NRF51xx Clock control
FICR Defines	Defined Constants and Types for the NRF51xx Factory information configuration registers
▼GPIO Defines	Defined Constants and Types for the NRF51xx General Purpose I/O
GPIO Pin Mode
GPIO Output Pin Pullup
GPIO Pin Identifiers
GPIO ports
GPIO drive configuration
GPIO sensing mechanism
▼I2C Defines	Defined Constants and Types for the NRF51xx I2C
I2C instances
I2C event -> task shortcuts	The effect of activated shortcut is, that upon I2C event triggering, the hardware will automatically start chosen task without intervention of the software
I2C interrupts
I2C peripheral mode
I2C frequency constants
POWER Defines	Defined Constants and Types for the NRF51xx Power control
▼PPI Defines	Defined Constants and Types for the NRF51xx Programmable peripheral interconnect
Channel identifiers
▼RADIO Defines	Defined Constants and Types for the NRF51xx 2.4GHz radio
Radio event -> task shortcuts
Radio interrupts
▼RTC Defines	Defined Constants and Types for the NRF51xx Realtime clock
RTC instances
▼TIMER Defines	Defined Constants and Types for the NRF51xx Timer
Timer_block
Timer event -> task shortcuts
▼UART Defines	Defined Constants and Types for the NRF51xx UART
UART instance
UART interrupt sources
UICR Defines	Defined Constants and Types for the NRF51xx User information configuraton registers
User interrupt service routines (ISR) prototypes for Nordic Semi NRF51 series
User interrupt service routines (ISR) defaults for Nordic Semi NRF51 series