Data Sheet

355
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181G–SAM-D21_Datasheet–09/2015
21. NVMCTRL – Non-Volatile Memory Controller
Note: The Read While Write (RWW) feature is only applicable for Device Variant B.
21.1 Overview
Non-volatile memory (NVM) is a reprogrammable flash memory that retains program and data storage even with power
off. It embeds a main array and a separate smaller Read While Write array intended for EEPROM emulation (RWWEE)
that can be programmed while reading the main array. The NVM Controller (NVMCTRL) connects to the AHB and APB
bus interfaces for system access to the NVM block. The AHB interface is used for reads and writes to the NVM block,
while the APB interface is used for commands and configuration.
21.2 Features
z 32-bit AHB interface for reads and writes
z Read While Write EEPROM (RWWEE) emulation area
z All NVM sections are memory mapped to the AHB, including calibration and system configuration
z 32-bit APB interface for commands and control
z Programmable wait states for read optimization
z 16 regions can be individually protected or unprotected
z Additional protection for boot loader
z Supports device protection through a security bit
z Interface to Power Manager for power-down of flash blocks in sleep modes
z Can optionally wake up on exit from sleep or on first access
z Direct-mapped cache
21.3 Block Diagram
Figure 21-1. Block Diagram
21.4 Signal Description
Not applicable
Command and
Control
NVM Interface
Cache
NVM Block
NVMCTRL
AHB
APB
Main Array
RWWEE Array