Download presentation
Presentation is loading. Please wait.
Published byTamsin Allison Modified over 8 years ago
1
Done By: Amnon Balanov & Yosef Solomon Supervisor: Boaz Mizrachi Project ID: d02310
2
Small sensors, with very low power consumption Planted under roads Performing monitoring of road maintenance status
3
Based on a PIC24 micro-processor Networking (two alternatives): o 2.4 GHz enabled by a MRF24J40 IEEE 802.15.4 Tx/Rx. o 433 MHz enabled by a MRF49XA Tx/Rx. Networking will run MiWi (Microchip propriatory S/W stack) ***All components are made by Microchip.
4
The design and implementation of a networking S/W stack who’s functions will be: 1. Transmissions of aquired data to a PC via similar unit 2. Parsing commands received from PC station 3. WAKE interrupts from sleep - for sensing sessions
5
Tx/Rx ◦ Communications with the PC unit microSD memory chip ◦ Stores aquired data PIC interrupts ◦ Wake/Transmission interrupts
6
Extra Board PICtail Evaluation Board – Explorer 16 MicroCTRL - PIC24FJ256GB110 Sensor Array Networking MRFJ40MB OR MRF49XA MEM- Flash & SRAM MEM- microSD SPI
7
Internal flash Program Memory- 256kB ◦ Current tests show 10% usage SRAM Data Memory- 16kB ◦ Current tests show 10% usage ◦ We will have a double buffer, a block length each, for communications (block=1kB; currently) 3 SPI Ports ◦ We will use one for the MRF & one for the µSD.
8
Uses 2.4GHz RF Uses O-QPSK modulation. Receiver FIFO- 144 byte, interrupts when a whole packet was received. Transmitter FIFO- 128 byte. Packet header length ~20 Bytes (TBD) Power: 19-23 mA Working ~2 µA Sleeping
9
Uses 433MHz RF Uses FSK modulation. Receiver FIFO- 16 bit, interrupts when full up to a certain point (configurable). Transmitter Registers- two 1-byte Registers, similar use to the PIC double buffer. Packet header length ~10 Bytes (TBD) Power: 11-15 mA Working 0.3 µA Sleeping
10
MRF24J40 ◦ 250 kbps transmission speed MRF49XA ◦ 115.2 kbps digital transmission speed ◦ 256 kbps analog transmission speed PIC24FJ256GB110 ◦ computational power of 16 MIPS ◦ sampling rate of 500 ksps microSD ◦ reads and writes are in the MB/s range
12
Definition and support the following working modes: ◦ Store samples (SS): Samples are stored in non-volatile memory for long period. ◦ Transmit samples (TS): Samples are read and transmitted from non-volatile memory through Wireless/UART/USB. ◦ Online sample and transmit (OST): Samples are read from sensor and then transmitted through UART/USB/Wireless, using internal SRAM memory (double buffer mechanism), without access to non-volatile memory.
13
The device is activated using a well defined CLI (Command Line Interface). The command line strings are received from either: ◦ TXRX wireless port ◦ USB port ◦ UART port ◦ Internal ROM table (Configuration table) Each command will be executed, and a prompt prefix, followed by the command result, will be returned to the command origin source (TXRX, USB or UART).
14
We will write a parser converting the different commands to a short field divided command. Work on the parser is in its early stages. For example: ◦ eeprom ◦ |5 bit command code| |3 bit sub-command| |8-bit optional|
15
As was decided, we use the MiWi SW Stack. ◦ MiWi is a proprietary stack designed by Microchip, free to use. The stack is implemented as general as possible and suits to the proposed HW networking modules. We use the MiWi P2P protocol.
16
The MiWi Protocol is divided into two parts: ◦ MiApp - upper level used to connect our application with the MiWi P2P protocol ◦ MiMAC - Using the MiMAC layer, we can easily switch between different RF transceivers such as MRF24J40 and MRF49XA.
18
This layer will give 5 major interfaces: ◦ Initialization- allows configuration of selected hardware. ◦ Hand-shaking-allows discovering and connecting to peers and network. ◦ Receiving- allows receiving information over the air. ◦ Transmitting- allows sending information over the air. ◦ Extended Functionality- allows environment noise and power saving control.
19
The MiMAC Layer allows us the abstraction of the Transceiver driver- we use it regardless of the driver used (at least in theory) Mainly implements the MiApp API
20
Allows the easy configuration of the whole application: Switching between Transceivers Enabling/Disabling different functions of the SW stack Further Development- Allows choosing the Protocol
21
TXInit() ◦ Initialize network parameters. ◦ The sensor creates a network. TXBatchInit() ◦ Initialize a new batch. TXBlock() ◦ Transmits block of size 1KB. TXStop() ◦ Ends transmission. TXRXDeviceTasks() ◦ This function will take care of the transceiver periodic tasks (handle TX and RX tasks).
22
INIT Send Command Interpret command & Send Data Go To Sleep Receive Data New/End Session The sensor sidePC side
23
In order to comply with time constraints of other parts of the WiStone we will test to see how big a payload we can use. In case we see a packet’s transmission cannot be interrupted and in order to allow easy coordination, we will make the transmission of a packet atomic (non-preemptive).
24
The two Transceivers support a sleep mode. They save the current status on configuration registers to allow easy wake up. The only way to wake up the transcievers is through pre-programmed timers on the transceivers or the PIC. We need to figure out how to allow access not at a pre-determined time.
25
Finishing software development & basic testing (3 weeks)- ◦ Completing code for: The Main Loop functions. Writing and documenting the parser (1 week) Outdoors Testing (1 week)-Testing the network capabilities under simulated conditions. Wrap-Up (1-2 weeks)- ◦ End of term presentation ◦ End of Project Report* Est. Total: 6-7 weeks. *Might be delayed because of Exam period
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.