Measuring Sam Da1 Power Consumption - Atmel SAMDA1 Xplained Pro User Manual

1. Option1: External power 5V is connected and detected. On board descrete high current output VREG is used to
regulate Vsupply from 5V to 3.3V and distribute it on the PCB and to the extension modules/PCBs. It overrides USB
power source.
2. USB power:
a. Option 2A: Embedded debugger USB plug is connected or/and
b. Option 2B: Target USB plug is connected
3. Option3: External 12VDC is connected to VS_LIN pin on HV header. It can override any other source of power
supplied (5V or 3V provided on PWR 4-pin header or any USB connector). Use header MCU_VCC_SEL and
EXT_VCC_SEL to select source of VCC from either (1) VS_LIN or (2) USB/PWR 4-pin header.
Note: External power is required when the 500mA through the USB connector is not enough to power a
connected USB device in a USB host application
Table 3-4 below shows how MCU_VCC_SEL (MCU VCC Selection) and EXT_VCC_SEL (Extension VCC Selection)
power headers can be used to select VCC source for SAMDA1J16A and EDBG MCUs.
To select VS_LIN (12VDC) as the source of power for SAMDA1 Xplained Pro PCB connect pin1-2 on MCU_VCC_SEL
header using a jumper.
To select 5V from either of the USB connectors or select VCC_P5V or VCC_P3V3 from the 4-pin power header as the
source of power for SAMDA1 Xplained Pro PCB connect pin 2-3 on EXT_VCC_SEL header using a jumper.
Power Header
MCU_VCC_SEL
EXT_VCC_SEL
3.3.2

Measuring SAM DA1 Power Consumption

As part of an evaluation of the SAM DA1 it can be of interest to measure its power consumption. Because the
PCB has a separate power plane (VCC_MCU_P3V3) it is possible to measure the current consumption by measuring
the current that is flowing into this plane. The VCC_MCU_P3V3 plane is connected via a jumper to the main power
plane (VCC_TARGET_P3V3) and by replacing the jumper with an ammeter it is possible to determine the current
consumption. To locate the current measurement header, refer to
Overview".
Warning: Do not power the board without having the jumper or an ammeter mounted since this can
cause SAM DA1
Table 3-4. Selecting VCC source (VS_LIN vs. USB/EXT5V/EXT3.3V)
Jumper placement
Pin 1-2
(VCC_LINTRX_P3V3 – to - VCC)
Pin 2-3
(VCC_P3V3 – to - VCC)
Pin 1-2
(VCC_LINTRX_P3V3 – to - VCC)
Pin 2-3
(VCC_P3V3 – to - VCC)
to be powered through its I/O pins and cause undefined operation of the device.
Configuration
VCC(SAMDA1J16A)=
VCC_LINTRX_P3V3
VCC(EDBG)= VCC_LINTRX_P3V3
VCC(SAMDA1J16A)= VCC_P3V3
VCC(EDBG)= VCC_P3V3
VCC(EXT1/EXT2/EXT3)=
VCC_LINTRX_P3V3
VCC(EXT1/EXT2/EXT3)=
VCC_P3V3
Figure 1-1, "SAMDA1 Xplained Pro Evaluation Kit
Atmel SAMDA1 Xplained Pro [USERGUIDE]
VCC Source
VS_LIN
USB/
VCC_P5/
VCC_P3V3
VS_LIN
USB/
VCC_P5/
VCC_P3V3
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