Mid Semester Presentation - High Speed Digital Systems Lab

Done By: Amnon Balanov & Yosef Solomon
Supervisor: Boaz Mizrachi
Project ID:
Small sensors, with very low power
Planted under roads
Performing monitoring of road maintenance
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.
The design and implementation of a
networking S/W stack who’s functions will be:
Transmissions of aquired data to a PC via
similar unit
Parsing commands received from PC station
WAKE interrupts from sleep - for sensing
◦ Communications with the PC unit
microSD memory chip
Stores aquired data
PIC interrupts
Wake/Transmission interrupts
Extra Board
MicroCTRL PIC24FJ256GB110
MEMFlash &
Evaluation Board – Explorer
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.
 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
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
◦ 250 kbps transmission speed
◦ 115.2 kbps digital transmission speed
◦ 256 kbps analog transmission speed
◦ computational power of 16 MIPS
◦ sampling rate of 500 ksps
◦ reads and writes are in the MB/s range
Definition and support the following working
◦ 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.
The device is activated using a well defined CLI
(Command Line Interface).
The command line strings are received from
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,
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 <sub command> <optional parameters>
◦ |5 bit command code| |3 bit sub-command| |8-bit optional|
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.
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.
This layer will give 5 major interfaces:
◦ Initialization- allows configuration of selected
◦ Hand-shaking-allows discovering and connecting
to peers and network.
◦ Receiving- allows receiving information over the air.
◦ Transmitting- allows sending information over the
◦ Extended Functionality- allows environment noise
and power saving control.
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
Allows the easy configuration of the whole application:
Switching between Transceivers
Enabling/Disabling different functions of the SW
Further Development- Allows choosing the Protocol
◦ Initialize network parameters.
◦ The sensor creates a network.
◦ Initialize a new batch.
◦ Transmits block of size 1KB.
◦ Ends transmission.
◦ This function will take care of the transceiver periodic
tasks (handle TX and RX tasks).
The sensor side
PC side
Send Command
Interpret command &
Send Data
Receive Data
Go To Sleep
New/End Session
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).
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.
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

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