Implementing Context Aware Applications Class 5

Agenda Review of TinyOS execution model Tutorial on TinyOS Code walk through Code quiz Assignment 2

Tiny OS Concepts Scheduler + Graph of Components  constrained two-level scheduling model: threads + events Component:  Commands,  Event Handlers  Frame (storage)  Tasks (concurrency) Constrained Storage Model  frame per component, shared stack, no heap Very lean multithreading Efficient Layering Messaging Component init Power(mode) TX_packet(buf) TX_packet _done (success) RX_packet_ done (buffer) Internal State init power(mode) send_msg (addr, type, data) msg_rec(type, data) msg_sen d_done) internal thread Commands Events

commands request action  ack/nack at every boundary  call cmd or post task events notify occurrence  HW intrpt at lowest level  may signal events  call cmds  post tasks Tasks provide logical concurrency  preempted by events Migration of HW/SW boundary TOS Execution Model RFM Radio byte Radio Packet bit byte packet event-driven bit-pump event-driven byte-pump event-driven packet-pump message-event driven active message application comp encode/decode crc data processing

Hardware Abstraction Architecture for TinyOS 2.x Combine the component model with a flexible, three-tier organization of the hardware abstraction HW platform 2 HPL 2 HAL 2 HIL 2 HW platform 3 HPL 3 HAL 3 HIL 3 HW platform 1 HPL 1 HAL 1 HIL 1 HW platform 4 HPL 4 HAL 4 HIL 4 Platform-specific applications Platform-specific applications Cross-platform applications Platform-independent hardware interface HW/SW boundary Hardware independence

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