14.3. Block Diagram
Figure 14-1. DSU Block Diagram
DSU
SWCLK
CORESIGHT ROM
DAP SECURITY FILTER
CRC-32
MBIST
CHIP ERASE
RESET
cpu_reset_extension
CPU
DAP
SWDIO
NVMCTRL
DBG
M
HIGH-SPEED
BUS MATRIX
M
S
debugger_present
DEBUGGER PROBE
INTERFACE
AHB-AP
PORT
14.4. Signal Description
The DSU uses three signals to function.
Signal Name
Type
Description
RESET
Digital Input
External reset
SWCLK
Digital Input
SW clock
SWDIO
Digital I/O
SW bidirectional data pin
Related Links
I/O Multiplexing and Considerations
on page 27
14.5. Product Dependencies
In order to use this peripheral, other parts of the system must be configured correctly, as described below.
14.5.1. IO Lines
The SWCLK pin is by default assigned to the DSU module to allow debugger probe detection and to
stretch the CPU reset phase. For more information, refer to
. The Hot-Plugging
feature depends on the PORT configuration. If the SWCLK pin function is changed in the PORT or if the
PORT_MUX is disabled, the Hot-Plugging feature is disabled until a power-reset or an external reset.
14.5.2. Power Management
The DSU will continue to operate in any sleep mode where the selected source clock is running.
Related Links
on page 188
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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