Datasheet

57
SAM9G45 [DATASHEET]
Atmel-6438O-ATARM-SAM9G45-Datasheet_08-Dec-15
The Debug Unit also manages the interrupt handling of the COMMTX and COMMRX signals that come from the
ICE and that trace the activity of the Debug Communication Channel.The Debug Unit allows blockage of access to
the system through the ICE interface.
A specific register, the Debug Unit Chip ID Register, gives information about the product version and its internal
configuration.
The SAM9G45 Debug Unit Chip ID value is 0x819B 05A2 and the extended ID is 0x00000004 on 32-bit width.
For further details on the Debug Unit, see Section 27. “Debug Unit (DBGU)”.
9.6.5 IEEE 1149.1 JTAG Boundary Scan
IEEE 1149.1 JTAG Boundary Scan allows pin-level access independent of the device packaging technology.
IEEE 1149.1 JTAG Boundary Scan is enabled when JTAGSEL is high. The SAMPLE, EXTEST and BYPASS
functions are implemented. In ICE debug mode, the ARM processor responds with a non-JTAG chip ID that
identifies the processor to the ICE system. This is not IEEE 1149.1 JTAG-compliant.
It is not possible to switch directly between JTAG and ICE operations. A chip reset must be performed after
JTAGSEL is changed.
A Boundary-scan Descriptor Language (BSDL) file is provided to set up test.