Microchip Technology ATSAMB11ZR, Руководство пользователя

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– Analog-to-Digital Converter
– Signal processing
– Control/communication interface to the EDBG
The current measurement front-end is a high side shunt measurement with a pre-amplifier and a second
active filter stage with gain as shown in
Figure 3-1 . The wide dynamic range is achieved by four
measurement ranges, which are defined by two shunt resistors and the two parallel second stage active
filters with gain.
3.3.2 Sample Rate
The raw sampling rate of the XAM is up to 250 kHz and with the default averaging configuration (average
of 16 samples), the actual output of the XAM is 16.67 ksps.
Info: The XAM output sample rate is not an integer fraction of the raw sampling.
3.3.3 Measurement Ranges and Accuracy
The XAM has four measurement ranges. These are defined by two shunt resistors and two gain stages.
Table 3-2. XAM Measurement Ranges and Accuracy
Measurement
Range Hardware Resolution Accuracy Comments
Range 1 Low current shunt and
high gain stage 20 nA 1 LSB ±1% Accuracy will decrease below
1 μA. Typical accuracy for
300 nA is 1 LSB ±10%.
Range 2 Low current shunt and
low gain stage 150 nA 1 LSB ±1%
Range 3 High current shunt and
high gain stage 10 μA 1 LSB ±1%
Range 4 High current shunt and
low gain stage 100 μA 1 LSB ±1% Accuracy will decrease above
100 mA. Typical accuracy is
1 LSB ±5% at 400 mA.
Maximum current is 400 mA.
The ranges are automatically switched by the XAM to achieve the best measurement results and the
currently active range is visualized in the
Data Visualizer front-end tool. The maximum voltage drop over
the shunt resistor is 100 mV, and the XAM switches the range automatically before reaching this limit.
3.4 Hardware Identification System
All Xplained Pro extension boards come with an identification chip (ATSHA204A CryptoAuthentication
™
chip) to uniquely identify the boards that are connected to the Xplained Pro evaluation kit. 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 evaluation kit, the information is read and sent to the
Atmel Studio. The following table shows the data fields stored in the ID chip with example content.
ATSAMB11ZR
©
2017 Microchip Technology Inc.
User Guide
DS70005334A-page 8