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

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.