•
SWD: The MCU in the XAM is programmed via SWD from the EDBG
•
GPIO: At least one GPIO that is connected to the EDBG from the target MCU is also connected to
the current measurement unit to enable the user to sync current measurements with his application
•
Clock sync: Synchronization signal to synchronize ADC measurements with EDBG
•
Reference clock: Reference clock for the XAM
3.2.3.
Sample Rate
The raw sampling rate of the Xplained Pro analog module (XAM) is up to 250kHz and with the default
averaging configuration (average of 16 samples) the actual output of the XAM is 16.67kSPS (note that
the XAM output sample rate is not an integer fraction of the raw sampling).
3.2.4.
Measurement Ranges and Accuracy
The Xplained Pro analog module has four measurement ranges. These are defined by two shunt resistors
and two gain stages.
Measurement
range
Hardware
Resolution Accuracy
Comments
Range 1
Low current shunt and
high gain stage
20nA
1 LSB ±1% Below 1μA the error will
increase. Typical error for
300nA is 1 LSB ± 10%
Range 2
Low current shunt and
low gain stage
150nA
1 LSB ±1%
Range 3
High current shunt and
high gain stage
10μA
1 LSB ±1%
Range 4
High current shunt and
low gain stage
100μA
1 LSB ±1% Above 100mA the error will
increase to 1 LSB ±5% at
400mA. Maximum current is
400mA
The ranges are switched automatically by the XAM to achieve best measurement results and the
currently active range is visualized in the
frontend tool. The maximum voltage drop
over the shunt resistor is 100mV and the XAM will switch the range automatically before this limit is
reached.
3.3.
Hardware Identification System
All Xplained Pro compatible extension boards have an Atmel ATSHA204 CryptoAuthentication
™
chip
mounted. This chip contains information that identifies the extension with its name and some extra data.
When an Xplained Pro extension is connected to an Xplained Pro MCU board the information is read and
sent to Atmel Studio. The Atmel Kits extension, installed with Atmel Studio, will give relevant information,
code examples, and links to relevant documents. The table below shows the data fields stored in the ID
chip with example content.
Table 3-2. Xplained Pro ID Chip Content
Data field
Data type
Example content
Manufacturer
ASCII string
Atmel'\0'
Product Name
ASCII string
Segment LCD1 Xplained Pro'\0'
Atmel SAM L22 Xplained Pro [USER GUIDE]
Atmel-42474B-SAM-L22-Xplained-Pro_User Guide-12/2015
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