Io工具使用

功能：

用 IO 指令可以实时读取或写入每个 IO 口的状态，这里简单介绍 IO 指令的使用。

配置：

make menuconfig -->utilities ---->打开 io

make menuconfig -->Global build settings --> kernel build option -->打开 /dev/mem virtual device  support

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root@OpenWrt:~# io --help Unknown option: ? Raw memory i/o utility - $Revision: 2.0 $   io -v -1|2|4 -r|w|a|o [-l <len>] [-f <file>] <addr> [<value>]       -v         Verbose, asks for confirmation     -1|2|4     Sets memory access size in bytes (default byte)     -l <len>   Length in bytes of area to access (defaults to                one access, or whole file length)     -r|w|a|o   Read from or Write to memory (default read)                optional write with modify (and/or)     -f <file>  File to write on memory read, or                to read on memory write     <addr>     The memory address to access     <val>      The value to write (implies -w)   Examples:     io 0x1000                  Reads one byte from 0x1000     io 0x1000 0x12             Writes 0x12 to location 0x1000     io -2 -l 8 0x1000          Reads 8 words from 0x1000     io -r -f dmp -l 100 200    Reads 100 bytes from addr 200 to file     io -w -f img 0x10000       Writes the whole of file to memory   Note access size (-1|2|4) does not apply to file based accesses.