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77 lines
2.8 KiB
Plaintext
77 lines
2.8 KiB
Plaintext
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(NOTE: view this file with a monospaced font)
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06. The eLua shell
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================================================================================
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After you burn eLua to your board and you connect the board to your terminal
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emulator running on the PC, you'll be greeted with the eLua shell prompt, which
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allows you to:
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- run 'lua' as you would run it from the Linux or Windows command prompt
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- upload a Lua source file via XMODEM and execute in on board
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- query the eLua version
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- get help on shell usage
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First you'll need to configure your terminal emulation program to connect to
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your eLua board. These are the parameters you'll need to set for your serial
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connection:
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- speed 115200, 8N1 (8 data bits, no parity, one stop bit)
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- no flow control
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- newline handling (if available): CR on receive, CR+LF on send
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After you setup your terminal program, press the RESET button on the bord.
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When you see the "eLua# " prompt, just enter "help" to see the on-line shell
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help:
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eLua# help
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Shell commands:
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help - print this help
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lua [args] - run Lua with the given arguments
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recv - receive a file (XMODEM) and execute it
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ver - print eLua version
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exit - exit from this shelll
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More details about some of the shell commands are presented below.
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The "recv" command
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================================================================================
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To use this, your terminal emulation program must support sending files via the
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XMODEM protocol. Both XMODEM with checksum (the original version) and XMODEM
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with CRC are supported, but only XMODEM with 128 byte packets is allowed (XMODEM
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with 1K packets won't work). The file size that you can upload is limited to 1024
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bytes, but this can be easily changed by modifying the "XMODEM_MAX_FILE_SIZE"
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macro in src/main.c:
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(BEGIN src/main.c)
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// Maximum file size that can be received via XMODEM
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// Should be a multiple of 128
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#define XMODEM_MAX_FILE_SIZE 1024
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(END src/main.c)
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To use this feature, enter "recv" at the shell prompt. eLua will respond with
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"Waiting for file ...". At this point you can send the file to the eLua board
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via XMODEM. eLua will receive and execute the file.
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The "lua" command
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================================================================================
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This allows you to start the Lua interpreter with command line parameters, just
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as you would do from a Linux or Windows command prompt. This command has some
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restrictions:
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- the command line can't be longer than 50 chars
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- character escaping is not implemented. For example, the next command won't work
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because of the \' escape sequences:
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eLua# lua -e 'print(\'Hello, World!\')' -i
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Press CTRL+Z to exit Lua
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lua: (command line):1: unexpected symbol near '\'
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However, if you use both '' and "" for string quoting, it will work:
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eLua# lua -e 'print("Hello, World")' -i
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Press CTRL+Z to exit Lua
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Lua 5.1.3 Copyright (C) 1994-2008 Lua.org, PUC-Rio
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Hello,World
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>
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