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NI Digital System Development Board User Manual
User Power Supplies Monitoring
The users have the ability to monitor the power of the two user supplies (3.3 V and 5 V) using
the dual channel analog-to-digital converter inside the Zynq (XADC). Both current and voltage
information from the two user supplies are routed to auxiliary analog inputs to the XADC as
differential pairs.
The XADC core within the Zynq is a dual channel 12-bit analog-to-digital converter capable of
operating at 1 MSPS. Either channel can be driven by any of the auxiliary analog input pairs.
The XADC core is controlled and accessed from the PL via the Dynamic Reconfiguration Port
(DRP). The DRP also provides access to voltage monitors that are present on each of the FPGA’s
power rails, and a temperature sensor that is internal to the FPGA. For more information on using
the XADC core, refer to the Xilinx document
7 Series FPGAs and Zynq-7000 All Programmable
SoC XADC Dual 12-Bit 1 MSPS Analog-to-Digital Converter
. It is also possible to access the
XADC core directly using the PS via the
PS-XADC
interface. This interface is described in full
in chapter 30 of the
Zynq Technical Reference Manual
.
The 3.3 V/5 V user voltages are sensed directly at the output through a 1/6 voltage divider. Note
that in case the user power supplies are disabled, the measurement signals
XADC_3V3_USER_/-, XADC_5V0_USER_/- are disconnected and
the XADC will read 0.The equation below shows how to compute voltage from the XADC
number:
Table 2.
Analog Input Pinout
Signal
XADC port
FPGA pin
XADC_5V0_USER_
AD5P
E21
XADC_5V0_USER_CURRENT-
AD5N
D21
XADC_5V0_USER_
AD4P
D20
XADC_5V0_USER_VOLTAGE-
AD4N
C20
XADC_3V3_USER_
AD6P
G19
XADC_3V3_USER_CURRENT-
AD6N
F19
XADC_3V3_USER_
AD14P
E19
XADC_3V3_USER_VOLTAGE-
AD14N
E20