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This program have three I/O functions that connect to UART driver via ioctl: (read(), write() and select()), but select() and write() change process stat to sleep mode until system don't receive or transmit all information via UART. "select" function is used to prevent that read function can be blocked when data aren't available. <br>The next images (program with debug gpio enable debug_gpio enabled and 300 bauds speed) show when program are in sleep/run mode process is executed or is waiting. Blue=UART1, Violet="write function time " and Green="select function time". When GPIO has HIGH value, process is blocked.<br>
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Click to enlarge image Conclusions: <br>
<br> '''Under Construction'''
[[Category:Communications]] [[Category:Work_in_progress]] [[Category:How_to_forge]]