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- Ezwsn: experimenting with wireless
- Lab 5: rf measurements
- 5.1. the importance of crc
Each packet is appended with a 16-bit Cyclic-Redundancy-
Check (
CRC ) which is used to detect accidental alterations of data during
transmission. CRC is computed over the data portion ofthe frame. Upon receiving a packet, the CC2500 recomputes a
CRC over the received data and compares that values with the received CRC. Amismatch indicates a corrupted packet; by default, the CC2500 silently drops
such a packet. You will disable CRC and see how often corrupted packets occur.
Running the code
- Copy code presented below
.
- Compile and download the code onto both boards
(Ctrl+D) .
- Connect one board to a computer using the USB programmer, and read its output
using PuTTY.
- Power the other with the battery packet and press the button. You should read
'abcdefghijklmnopqrstu' on PuTTY.
- Repeat his multiple times by moving away the sending node; you should see
some alterations to the output text. If CRC was enabled, these packet would havebeen dropped by the CC2500 and you wouldn't see them on the screen.
- You may wish to speed things up by changing
P1IFG&= ~0x04; to
P1IFG |= 0x04; on the sender's side
so one press of the button generates an infinite stream of packets. Similarly, youmay wish to reduce its transmission power as explained in
4.3. Continuous Tx/Rx .
#include "radios/family1/mrfi_spi.h"
#include "mrfi.h"mrfiPacket_t packetToSend;
int main(void){
BSP_Init();P1REN |= 0x04;
P1IE |= 0x04;MRFI_Init();
mrfiSpiWriteReg(PATABLE,0xBB);mrfiSpiWriteReg(PKTCTRL0,0x41);
P3SEL |= 0x30;UCA0CTL1 = UCSSEL_2;
UCA0BR0 = 0x41;UCA0BR1 = 0x3;
UCA0MCTL = UCBRS_2;UCA0CTL1&= ~UCSWRST;
MRFI_WakeUp();MRFI_RxOn();
__bis_SR_register(GIE+LPM4_bits);}
void MRFI_RxCompleteISR(){
uint8_t i;P1OUT ^= 0x02;
mrfiPacket_t packet;MRFI_Receive(&packet);
char output[]= {" \r\n"};
for (i=9;i<packet.frame[0];i++) {output[i-9]=packet.frame[i];
}TXString(output, (sizeof output));
}#pragma vector=PORT1_VECTOR
__interrupt void Port_1 (void){
P1IFG&= ~0x04;
char character = 'a';uint8_t index;
mrfiPacket_t packet;for (index=9;index<30;index++) {
packet.frame[index]=character++;
}packet.frame[0]=++index;MRFI_Transmit(&packet, MRFI_TX_TYPE_FORCED);
P1OUT ^= 0x01;}
Questions & Answers
the study of living organisms and their interactions with one another and their environments
AI-Robot
HOW CAN MAN ORGAN FUNCTION
the diagram of the digestive system
allimentary cannel
Ogenrwot
They formed in two ways first when one sperm and one egg are splited by mitosis or two sperm and two eggs join together
Oluwatobi
Genetics is the study of heredity
Misack
how does twins formed?
Misack
discuss biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles
the study of living organisms and their interactions with one another and their environment.
Wine
discuss the biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles in an essay form
list any five characteristics of the blood cells
Shaker
lack electricity and its more savely than electronic microscope because its naturally by using of light
advantage of electronic microscope is easily and clearly while disadvantage is dangerous because its electronic. advantage of light microscope is savely and naturally by sun while disadvantage is not easily,means its not sharp and not clear
Abdullahi
cell theory state that every organisms composed of one or more cell,cell is the basic unit of life
Abdullahi
is like gone fail us
DENG
cells is the basic structure and functions of all living things
Ramadan
is organisms that are similar into groups called tara
Yamosa
in what situation (s) would be the use of a scanning electron microscope be ideal and why?
A scanning electron microscope (SEM) is ideal for situations requiring high-resolution imaging of surfaces. It is commonly used in materials science, biology, and geology to examine the topography and composition of samples at a nanoscale level. SEM is particularly useful for studying fine details,
Hilary
cell is the building block of life.
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Source:
OpenStax, Ezwsn: experimenting with wireless sensor networks using the ez430-rf2500. OpenStax CNX. Apr 26, 2009 Download for free at http://cnx.org/content/col10684/1.10
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