Networked CAN Bus Controller - UTC Aerospace Team 1907: Matthew - - PowerPoint PPT Presentation

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Sep 23, 2022 206 likes •391 views

Networked CAN Bus Controller - UTC Aerospace Team 1907: Matthew Cox, Pawel Bezubik, John Nguyen Advisor: Dr. Chandy Sponsor: Chris Soumakis, William Villano, Chris Grant Project Outline Design a CAN Bus controller for an aerospace PCI

SLIDE 1

Networked CAN Bus Controller - UTC Aerospace

Team 1907: Matthew Cox, Pawel Bezubik, John Nguyen Advisor: Dr. Chandy Sponsor: Chris Soumakis, William Villano, Chris Grant

SLIDE 2

Project Outline

Design a CAN Bus controller

for an aerospace PCI rack.

Allows for distributed

control and sensing of multiple devices.

Create an interactive sensor

network using multiple nodes.

SLIDE 3

Sponsor Requirements - General Overview

Design a controller to control and monitor different types of I/O such as sensors, switches,

motors and valves

Utilize CAN bus for communication between devices and design a protocol on top of CAN

to relay information between devices.

Design a PCB that fits the VITA 20 Standard Single Width Form Factor for PCI Mezzanine

Cards (PMC).

SLIDE 4

Progress

MCU dev board arrived and setup
CAN Bus software demo completed

○ Send and receive functions ○ CAN interrupt handler

Finalizing software architecture
Writing test code for peripherals
Working on circuit design and

analysis

SLIDE 5

ATSAMC21J18A

Provides most flexibility in terms of Serial I/O
True 5V tolerant ARM Microcontroller
On-board CAN Controller with superior features:

○ 64 dedicated receive buffers ○ 32 dedicated transmit buffers ○ 2 configurable receive FIFOS

Comprehensive set of peripherals and features
Best benefits for unit cost

SLIDE 6

Start at CAN message
Message from CAN decides

function of MCU

Emergency Flags can also be

interrupts

Software High Level

SLIDE 7

Software Polling

Variable Timer controls polling interval

time

Continuous input from sensors
Faster access to sensor data

SLIDE 8

CAN Network Protocol

Data Bits Function ID[28:26] Priority Level ID[25:18] Transmit Device ID ID[17:9] Receive Device ID ID[8:4] Packet Type ID[3:0] Command

SLIDE 9

Discrete Interface

2-3 required on board
Convert voltage range to discrete input
Scale circuit to 10mA when switch closes
Analyzing 2 options

SLIDE 10

Discrete Input - First option

Early Design of Current

Threshold Circuit

Schottky diode to reduce output

swing to minimize slew rate

Zener diode for reference

voltage

Inverting input will be slightly

above/below ground

SLIDE 11

Discrete Input - Second option

Current shunt resistor +

Differential Current Sense Amplifier IC

Allows for current to be measured

as a voltage based on shunt value

Can allow for variable current

threshold defined in software

SLIDE 12

Analog Interface

Unity gain amplifier
0-10V inputs to be utilized for various sensors
5 Inputs required on board
Buffer and scale voltages down to 0-5V
Read into MCU

SLIDE 13

Current Driver

Used to drive a coil and create a deflection/holding torque
Requires an accurate current source up to 200mA
Controlled by ~22 kHz PWM command.
Example circuit withheld by sponsor due to use of company IP

SLIDE 14

PCB Form Factor

Layout according to VITA

20 Standard

Specification is for PCI

Mezzanine Cards (PMC)

Board will be secured into

enclosure with other cards

We will be utilizing Single

Width specification size: 143.75mm x 74mm

SLIDE 15

Budget

Sponsor has no

set development budget

Items Quantity Price MCU Dev Kit - ATSAMC21J18A 1 $52.49

SLIDE 16

Timeline

Finish I/O circuit designs by 12/22/18
Peripheral test code completed by 12/22/18
Breadboard Testing: 12/30/18 - 1/21/19
Design Revisions / Prototype PCB: 1/22/19 - 2/21/19
Test first PCB: 2/22/19 - 3/4/19
PCB Revisions / Corrections: 3/5/19 - 4/1/19
Final Testing / Extra Time: 4/2/19 - 4/22/19
Final Report: 4/22/19 - 4/29/18

SLIDE 17

Thank You

We look forward to continuing our design. Any feedback is much appreciated.