# Peripherals

The RSL15 system has a number of peripherals to support auxiliary non-RF tasks. These peripherals are described briefly in the sections below, and in detail in Activity Counters.

Additional peripherals that are only accessible to the Arm Cortex-M33 processor have been defined by Arm and integrated into the RSL15 system. These blocks are described in Private Peripherals.

## Activity Counter

The activity counters help to analyze how long the RSL15 system has been running, and how much the CPU and the flash have been used by the application in a period of time. This is useful information for estimating and optimizing the power consumption of the application.

For HAL firmware information related to the activity counters, see the RSL15 Firmware Reference: Activity Counter.

## Asynchronous Clock Counter

The asynchronous clock counter (ASCC) measures the timing of a clock signal, such as STANDBYCLK or a clock provided on a GPIO input, relative to the system clock.

For HAL firmware information related to the ASCC, see the RSL15 Firmware Reference: Asynchronous Clock Counter.

## CRC

This block provides an implementation of two standard cyclic redundancy code (CRC) algorithms (CRC-CCITT and CRC-32 - IEEE 802.3), which can be used to ensure the integrity of a user application's code and data.

For HAL firmware information related to the CRC, see the RSL15 Firmware Reference: Cyclic Redundancy Check.

## DMA Controller

The Direct Memory Access (DMA) Controller allows background transfers between peripherals and memories without processor intervention. The system can be in the idle low power state, with the processor waiting for an interrupt or event, or in use for other computational tasks while the transfer occurs. The DMA is connected to the processor, peripherals, and RAM memories, and has four independent channels.

For HAL firmware information related to the DMA, see the RSL15 Firmware Reference: Direct Memory Access.

## Flash Copier

The flash copier supports several operations on data that has been stored to flash memory:

- A background copy of data stored in the flash to another area in memory
- A background copy of flash data to the CRC block for data integrity validation
- A comparison operation over a block with a fixed value, used primarily to validate if data has been erased or has been cleared by being overwritten to zero

For HAL firmware information related to the flash copier, see the RSL15 Firmware Reference: Flash Copier

## Time of Flight

RSL15 features a time of flight module, which enables measurement of how long certain operations take to complete, particularly RF operations.

The time of flight module can be stopped and started through software control, or via hardware control using RF front-end interrupts. Features of the module include averaging, maximum and minimum data point recording, sample counts, and automatic data transfer via DMA.

For more information about the time of flight module and its use, see Time of Flight.

For HAL firmware information related to time of flight, see the RSL15 Firmware Reference: Time of Flight.

## Timers

There are four independent 24-bit timers that can operate as single-shot, multi-shot, or free-run. Interrupt or GPIO output can be configured with timer value capture on timer expiration.

For HAL firmware information related to timers, see the RSL15 Firmware Reference: General-Purpose Timer.

## Watchdog

The watchdog timer must be reloaded at regular intervals. If it is not refreshed and the timer expires, a reset is issued to the system. The watchdog timer is disabled when the RSL15 system is connected to an external debugger, but otherwise cannot be disabled.

For HAL firmware information related to the watchdog timer, see the RSL15 Firmware Reference: Watchdog.