Download
1 / 13
130 likes | 261 Views
Implementation of Embedded OS. Lab5 Real-time Programming on μ C/OS-III. Goal. Source : http://micrium.com/page/home. Practice real-time programming on μ C/OS-III. Environment. Host System Windows XP Build System VirtualBox + Ubuntu 8.04 Target System
E N D
Implementation of Embedded OS Lab5 Real-time Programming on μC/OS-III
Goal Source: http://micrium.com/page/home Practice real-time programming on μC/OS-III. /13
Environment • Host System • Windows XP • Build System • VirtualBox + Ubuntu 8.04 • Target System • PTK development board (STM32F207) • Software • Reference codes • You can download them from RSWiki IEOS Course Software /13
Scenario Sensor Message Channel (higher priority) Server Data Channel (lower priority) /13 • In sensor network, the main job of sensors is to transmit collected data to a server. • It is common to use multiple communication channels with different levels of priority between a sensor and the server. • Monitoring data versus alarm events • Control messages versus data traffic • …
Problem TCP Sockets Sensor (PTK) Message Channel Server (Ubuntu) Data Channel Message Channel Data Channel PTK Ubuntu PTK Ubuntu Request1 Packet1 10ms Response1 20ms random (ms) Packet2 Request2 ⁞ Response2 ⁞ Request100 Response100 In this lab, we would like to implement the following communication model. /13
Specification (1/8) 4 bytes REQ_TS_SEC 4 bytes REQ_TS_USEC Request Message /13 • Request Message Format • REQ_TS_SEC: a four-byte unsigned integer representing the time when the request is sent in seconds • REQ_TS_USEC: a four-byte unsigned integer representing the fractional part of the time when the request is sent in microseconds
Specification (2/8) *Please refer to P.11 for how to obtain these values. 4 bytes RECV_TS_TICK 4 bytes RECV_TS_CYCLE 4 bytes REP_TS_TICK 4 bytes REP_TS_CYCLE Response Message /13 • Response Message Format • RECV_TS_TICK: a four-byte unsigned integer representing the arrival time of the request in ticks* • RECV_TS_CYCLE: a four-byte unsigned integer representing the arrival time of the request in cycles* • REP_TS_TICK: a four-byte unsigned integer representing the time when the response is sent in ticks • REP_TS_CYCLE: a four-byte unsigned integer representingthe time when the response is sent in cycles
Specification (3/8) 2 bytes LEN DATA LEN bytes Data Packet /13 • Data Packet Format • LEN: a two-byte unsigned short integer representing the length of data payload • The value of LEN should range from 1 to 4095. • DATA[0..LEN-1]: data payload of LEN bytes • You should fill DATA with the values [0, 255] in sequence and wrapping around when LEN is larger than 255. • The data length and transmission interval are generated randomly by the algorithm shown on the next page.
Specification (4/8) unsigned int my_seed[2] = {0x1234, 0x5678}; unsigned int my_rand(int idx) { my_seed[idx] = ((my_seed[idx] * 1103515245) + 12345) & 0x7fffffff; return my_seed[idx]; } /13 • Random Number Generator • Please use the following C codes to generate random numbers. • Use (my_rand(0) % PACKET_SIZE) to generate random numbers for LEN, PACKET_SIZE <= 4096. • Use (my_rand(1) % TRANS_INT) to generate random numbers for transmission interval, TRANS_INT = 20.
Specification (5/8) /13 • Timing • You need to measure the time of the following events for all messages and data. • In μC/OS-III • Receiving time of each message request • Sending time of each message response • In Linux • Sending time of each message request • Receiving time of each message response • Start time of each incoming data transmission • Finish time of each data transmission • All measurement should be done right before the socket function send or after the socket function read. • You should stop the measurement as soon as the last response is processed.
Specification (6/8) /13 • Timing Functions • In μC/OS-III, you should use OSTimeGet to obtain the current value of the tick counter, and use OS_TS_GET to obtain the current value of the CPU cycle counter. • In Linux, you should use gettimeofday for all timing.
Specification (7/8) /13 • Program Input • N, PACKET_SIZE,TRANS_INT • Program Output • In Linux, for each pair of request/response messages, output a comma-separated list per line as follows. • MSG_NO, REQ_TS_SEC, REQ_TS_USEC, RECV_TS_TICK, RECV_TS_CYCLE, REP_TS_TICK, REP_TS_CYCLE, REP_RECV_TS_SEC, REP_RECV_TS_USEC • MSG_NO is the message number from 1 to N. • REP_RECV_TS_SEC/REP_RECV_TS_USEC is the time when the response is received in Linux. • Others are specified in the message formats.
Specification (8/8) /13 • Program Output (cont’d) • After the process receives N messages, output the statistics as follows. • REQ_INT_AVG, REQ_INT_VAR, REP_INT_AVG, REP_INT_VAR, DATA_RECV_SUM, DATA_RECV_INT_SUM, MESG_TRANS_INT_MAX • REQ_INT_AVG and REP_INT_AVG are the averages of time interval between two consecutive request and response in microseconds. • REQ_INT_VAR and REP_INT_VAR are the variance of time interval between two consecutive request and response, where the variance is calculated as . • DATA_RECV_SUM is the total number of received data in bytes. • DATA_RECV_INT_SUM is the sum of receiving time for all data packets in microseconds, where the receiving time is calculated as (finished time – start time) of that data transmission. • MESG_TRANS_INT_MAX is the maximum time of sending or receiving a message, the difference of start time on each side in microseconds.
