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32 lines
1.4 KiB
Text
32 lines
1.4 KiB
Text
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Example Description
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This example describes how to use freertos tickless with uart interruptable interface
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Requirement Components:
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USBtoTTL adapter
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Connect to PC
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- Connect Ground: connect to GND pin via USBtoTTL adapter
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- Use UART1
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GPIOA_0 as UART1_RX connect to TX of USBtoTTL adapter
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GPIOA_4 as UART1_TX connect to RX of USBtoTTL adapter
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We also need connect GPIOC_1 as gpio interrupt which parallel with log uart rx pin.
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In this example, freertos will enter/leave tickless automatically.
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User can type continuous "Enter" in uart or log uart to wake system if system is in tickless.
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System is keep awake until user type a command via uart.
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There are some features in this example:
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(1) We replace tickless' sleep function with system sleep api which save more power.
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(2) Freertos enter tickless if the wakelock bit map is 0.
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It means there is no function require system keep awake.
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By default there is WAKELOCK_OS keep system awake.
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So we need release this WAKELOCK_OS enable tickless mode.
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(3) We configure uart rx as gpio interrupt mode. This make uart can wake system.
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NOTICE: If you don't want loss any data from treating UART signal as GPIO interrupt,
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you can set FREERTOS_PMU_TICKLESS_PLL_RESERVED to 1 in "platform_opt.h".
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It will reserved PLL clock in tickless and UART can receive the whole data.
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But it also cost more power consumption.
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