SAM4L Datasheet, PDF (1082/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
41. Cyclic Redundancy Check Calculation Unit (CRCCU)
Rev: 2.0.2.0
41.1 Features
• Performs Cyclic Redundancy Check Operation on Memory Area
• Single AHB Master Interface
• APB Configuration Interface
41.2 Overview
The CRCCU performs CRC check on memory area.
41.3 Block Diagram
Figure 41-1. CRCCU Block Diagram
APB
CLK_CRCCU_APB
Interface
AHB
DMA
CRC
irq
CLK_CRCCU_AHB
41.4 Product Dependencies
In order to use this module, other parts of the system must be configured correctly, as described
below.
41.4.1
Power Management
CRCCU stops functioning when the system enters a sleep mode that disables its clock. CRCCU
resumes operation after the system wakes up from sleep mode.
41.4.2 Clocks
CRCCU clocks (CLK_CRCCU_APB, CLK_CRCCU_AHB) are generated by the Power Man-
ager. they can be disabled either manually through the user interface of the Power Manager or
automatically when the system enters a sleep mode that disables the clocks to the peripheral
bus modules.
41.4.3 Interrupts
The CRCCU interrupt request line is connected to the NVIC. Using the CRCCU interrupt
requires the NVIC to be configured first.
41.4.4
Debug Operation
When an external debugger forces the CPU into debug mode, CRCCU continues normal opera-
tion. If the CRCCU is configured in a way that requires it to be periodically serviced by the CPU
through interrupts or similar, improper operation or data loss may result during debugging.
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