lecture-7-cho_pte587_sensornet1-feb-24-2011

3211 usc pte587 20 state machine programming model

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Unformatted text preview: rdless Phones Digital/Analog •  Single Channel –  Cellular Phones •  Mul; ­channel, Base sta;on controlled –  802.11 •  “wireless Ethernet” –  Bluetooth •  Emerging, low ­power frequency hopping 3/2/11 USC  ­ PTE587 17 What is in your cell phone? •  Texas Instrument’s TCS2500 Chipset 270.833 kbps ARM9, 120Mhz + DSP 3/2/11 USC  ­ PTE587 18 Third Decision: Sooware •  TinyOS: famous Berkeley SW –  OS/Run;me model designed to manage the high levels of concurrency required –  Gives up IP, sockets, threads –  Uses state ­machine based programming concepts to allow for fine grained concurrency –  Provides the primi;ve of low ­level message delivery and dispatching as building block for all distributed algorithms •  Many, many, many others 3/2/11 USC  ­ PTE587 19 Key Sooware Requirements •  •  •  •  •  Capable of fine grained concurrency Small physical size Efficient Resource U;liza;on Highly Modular Self Configuring 3/2/11 USC  ­ PTE587 20 State Machine Programming Model •  System composed of state machines •  Command and event handlers transi;on modules from one state to another –  Quick, low overhead, non ­blocking state transi;ons •  Many independent modules allowed to efficiently share a single execu;on context 3/2/11 USC  ­ PTE587 21 Tiny OS Concepts Scheduler + Graph of Components Constrained Storage Model –  Frame per component –  Shared stack –  No heap USC  ­ PTE587 TX_packet(buf) Power(mode) Lean Mul;threading 3/2/11 Internal State internal thread init •  msg_send_done) Messaging Component RX_packet_d one (buffer) •  Commands Event Handlers Frame (storage) Tasks (concurrency) Events TX_packet_do ne (success) –  –  –  –  send_msg (addr, type, data) Component: init •  Commands msg_rec(type, data) –  Constrained Two ­level Scheduling Model: –  Threads + Events power(mode) •  22 application Applica;on = Graph of Components Route map router sensor appln bit byte packet Active Messages Radio Packet Radio byte RFM 3/2/11 Serial Packet UART Temp photo SW HW ADC cloc...
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