Microchip Technology DIGITAL POWER, Руководство пользователя

Страница: 11 / 22

Overview

2018 Microchip Technology Inc. DS50002814A-page 11
1.2.3 Grounding System
The entire board ground potential is connected together and forms one galvanically
common domain. The labels, “Analog” and “Digital”, indicate the geometrical domain.
The copper pour connected to the ground potential is split into two geometrical
domains, but the two geometrical domains are jointed together under the PIM socket,
thus improving the signal integrity and keeping noise confined to near their sources.
1.2.4 External Analog Signal Input
It is possible to insert an analog signal to any ADC input from a signal generator via a
standard BNC connector. The input impedance is 50

. Input signals between the
ground and +3.3V are accepted. An overvoltage protection is implemented on this input
with a series resistor, and a pair of parallel diodes between the ground and the positive
supply rail.
1.2.5 DC Level Insertion
Two on-board potentiometers are connected between the ground and the +3.3V supply
rail to provide two stable DC levels. The two DC levels can be set independently with
potentiometers: P1 and P2. These DC signals can be used as an input signal to any
ADC input. The DC level set by P1 can be connected to the upper half, while P2 can
be connected to the lower half of the ADC inputs, at the analog input connection
jumpers.
1.2.6 Analog Input Connection Jumpers
The ADC inputs of the DP PIM board can be accessed directly from the pin header (J3)
located at the left side of the board. These inputs can also be connected to either the
external analog signal input (J7) or to the DC level insertion, respectively. The
three-row pin header matrix, J4, J5, J6 (No. 7 in
Figure 1-1 ), forms a three-pin selection
jumper for each ADC input. When placing a jumper over the left, or over the right and
the middle pins, the corresponding ADC input can be connected to the extra input as
indicated on the silkscreen. The left side pins connect the external analog signal input,
while the right side pins connect the DC level insertion to the given ADC input. Two
positions on the DAC outputs are not connected. The pins on those positions are just
placeholders to keep the pin order. Three pins are connected to GND at both ends of
the jumper row. Jumpers can be stored on those pins if not needed. Two jumpers are
provided in the kit.
1.2.7 Push Buttons
There are two push buttons on the board: SW1 and SW2. Push button SW2, which is
directly connected to the RESET pin of the DP PIM board, is for the system Reset. For
dual core devices, this RESET is connected to the Master core Reset line. Push button
SW1 is a general purpose user interface connected to the TP27 test point and the
corresponding pin on the DP PIM.
1.2.8 MikroBUS™ Socket
A standard extension socket (J10) is provided on the board for mikroBUS
click boards™. The functionality of the board can be easily extended by using this
feature. The DP PIM board communicates with the mikroBUS socket via dedicated SPI
lines and the I
2
C bus. Both +5V and +3.3V supply rails are connected to the
corresponding pins of the mikroBUS socket. The Reset button is connected to the
mikroBUS socket RESET pin.