Microcontroller Solutions TechZone Magazine, April 2011 - Digikey

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Figure 14: Character data fi lter usage. Using the RSS/XML feed reader Using the RSS/XML feed reader fi rmware is easy: Figure 12: RSS/XML datafl ow diagram. The fi lter takes in an XML or RSS data stream and a list of tags. It outputs only the character data from the selected tags. The tag list is an array of pointers to those tag strings that need to be fi ltered. Normally the fi lter returns 0. When the fi lter processes the “>” in a tag in the list, it returns into the fi lter array the index+1 for the tag that it found. Example: after detecting a tag in an RSS or XML stream the fi lter will return 1. After detecting a tag in a stream the fi lter will return 2. The fi lter returns 0 if a tag is not found. Const unsigned char *tag_filter[] = { {(const unsigned char *)”title”}, {(const unsigned char *)”description”}, {(const unsigned char *)””} }; Figure 13: Sample tag_fi lter pointer array. 1. Set the variable url to the URL or to the desired RSS or XML server. static const unsigned char url[] = “http://www.weather.gov/data/current_ obs/KUGN.rss”; 2. Set the tag_fi lter[] to the type of data you want to display. For RSS feeds, and would be a fi rst choice. For XML feeds, this could be any tag name depending on the information. const unsigned char *tag_filter[] = { {(const unsigned char *)”title”}, {(const unsigned char *)”description”}, {(const unsigned char *)””} }; 3. Set the character buffer size large enough to collect your fi ltered data. #define RSS_CHARACTER_BUFF_SIZE2048 4. Compile the project and fl ash it to the board. After the TCP/IP stack comes up, these actions occur: 1. The DHCP client automatically acquires an IP address and DNS IP address. 2. It displays and speaks a title screen. 3. It connects to the server specifi ed in the URL. 4. The status of the connection is displayed and spoken. 5. The fi le is downloaded from the server using the HTTP client. 6. After the connection closes, the fi le is displayed and spoken. 7. The RSS/XML feed reader sleeps, waiting for either SW1 or SW2 to be pushed. When that happens, a connection is initiated to the server specifi ed in the URL that starts the download/display/ speak process all over again. 34
XML Streams For XML streams, the EMG_rss_text_fi lter() return value is used to determine which tag is applied to the data that comes after the tag. This allows another const array containing more descriptive names to be used to describe the data from the tag. Simply use the EMG_rss_text_fi lter() return value–1 to index into a descriptive name array, then send the indexed string into the character buffer before leaving the RSS callback function. The XML fi lter will then place the data from the tag in the character fi lter directly after the descriptive name. Conclusion Adding Ethernet to embedded products provides a level of connectivity never before available in the embedded space. Embedded devices can be networked together using the same cables and hardware used by the industry to connect PCs together. The embedded device can become part of the PC network. Ethernet and TCP/IP enable the embedded device to connect to the ultimate network, the Internet. After the embedded device is connected to the Internet it is available to the world, and controllable or viewable from anywhere. The possibilities are endless, from remote monitoring and control to distributed control, and even real-time, world-wide data presentation through the RSS feed reader. i.MX35 Processor Freescale Semiconductor The i.MX35 processor is the latest series from Freescale. This chip includes an increased level of integration and support, while maintaining low-power requirements. Digi-Key’s product training module featuring the i.MX35 processor aids purchasers in understanding the many benefi ts of integrating this device into designs and projects. Applications for this processor include portable navigation devices, printers, and eBooks to name a few. www.digikey.ca/ptm Kinetis <strong>Microcontroller</strong>s Design Potential. Realized. • The fi rst broad-market mixed signal MCU family based on the ARM ® Cortex-M4 core • One of the most comprehensive ARM enablement portfolios in the industry • Over 200 pin-, peripheral- and software-compatible MCUs with exceptional performance, memory and feature scalability • Innovative 90 nm thin-fi lm-storage fl ash technology with FlexMemory delivering high-endurance EEPROM • Ultra-low-power performance and rich mixedsignal integration Kinetis Family Positioning K10 Family: 32 KB to 1 MB, ultra-low power, advanced mixed signal, touch sensing, CAN K20 Family: 32 KB to 1 MB, ultra-low power, advanced mixed signal, touch sensing, CAN, USB OTG K30 Family: 32 KB to 512 KB, ultra-low power, advanced mixed signal, touch sensing, CAN, segment LCD K40 Family: 32 KB to 512 KB, ultra-low power, advanced mixed signal, touch sensing, CAN, USB OTG, segment LCD K60 Family: 256 KB to 1 MB, ultra-low power www.digikey.ca/freescale-mcu www.digikey.ca/microcontroller 35
Page 1 and 2: MICROCONTROLLER LIGHTING SOLUTIONS
Page 3 and 4: MICROCONTROLLER SOLUTIONS TZ M 112.
Page 5 and 6: Editorial Comment The Energy Manage
Page 7 and 8: The Ultra-Low-Power USB Revolution
Page 9 and 10: Figure 2: MSP430 USB microcontrolle
Page 11 and 12: MSP430x5xx Overivew Texas Instrumen
Page 13 and 14: The thermistor used in the circuit
Page 15 and 16: Introducing a Second MCU to Embedde
Page 17 and 18: Introduce complexity in stages: Do
Page 19 and 20: Eliminating the Parallel/Serial Tra
Page 21 and 22: Physical interface Figure 3 shows t
Page 23 and 24: Configure the IP address of the rou
Page 25 and 26: Usage considerations with uIP TCP/I
Page 27 and 28: The transport layer adds the most c
Page 29 and 30: DHCP client The Dynamic Host Config
Page 31 and 32: Voice synthesizer The RC Systems V-
Page 33: Drawback of XML documents The probl
Page 37 and 38: Computer connectivity The tremendou
Page 39 and 40: Are you a Microcontroller Solution
Page 41 and 42: Examples of deeply embedded, Intern
Page 43 and 44: less than what most people demand f
Page 45 and 46: Table 1: Reflex producers. Module R
Page 47 and 48: The function PRS_ScanChannel(TIMER_
Page 49 and 50: Figure 2: Schematic diagram from th
Page 51 and 52: 6. If not, it attempts to retransmi
Page 53 and 54: • How fast do I have to read the
Page 55 and 56: 1) Can.h The CAN structure CAN_Msg:
Page 57 and 58: Two IRQ events are shown. Note an I
Page 59 and 60: Figure 3: Timeline window. Another
Page 61 and 62: The Heartbeat Behind Portable Medic
Page 63 and 64: While MCU suppliers continue to inn
Page 65 and 66: USB 3.0 is clearly overkill for HID
Page 67 and 68: Digi-Key, at your service. Programm

Microcontroller Solutions TechZone Magazine, April 2011 - Digikey

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