OVMS3-idf/examples/system/console/README.md
2017-08-21 15:58:27 +08:00

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# Console example
This example illustrates usage of `console` component to create an interactive shell.
## Configuring UART and VFS
``initialize_console`` function configures some aspects of UART and VFS relevant to the operation of console:
- By default `stdin` and `stdout` are buffered streams. This means that the text written to `stdout` will not be immediately sent to UART. This is not the desirable behavior for the console, so buffering for `stdin` and `stdout` is disabled using `setvbuf` function.
- Line endings are configured to match those expected/generated by common serial monitor programs, such as `screen`, `minicom`, and the `idf_monitor.py` included in the SDK. The default behavior for these commands is:
- When 'enter' key is pressed on the keyboard, `CR` (0x13) code is sent to the serial device.
- To move the cursor to the beginning of the next line, serial device needs to send `CR LF` (0x13 0x10) sequence.
- UART driver is initialized, and VFS is configured to use UART driver's interrupt-driver read and write functions.
## Line editing
The main source file of the example illustrates how to use `linenoise` library, including line completion, hints, and history.
## Commands
Several commands are registered using `esp_console_cmd_register` function. See `register_wifi` and `register_system` functions in `cmd_wifi.c` and `cmd_system.c` files.
## Command handling
Main loop inside `app_main` function illustrates how to use `linenoise` and `esp_console_run` to implement read/eval loop.
## Argument parsing
Several commands implemented in `cmd_wifi.c` and `cmd_system.c` use Argtable3 library to parse and check the arguments.
## Command history
Each time a new command line is obtained from `linenoise`, it is written into history and the history is saved into a file in flash memory. On reset, history is initialized from that file.
# Example output
Here is an sample session with the console example. GPIO15 is connected to GND to remove boot log output.
```
This is an example of ESP-IDF console component.
Type 'help' to get the list of commands.
Use UP/DOWN arrows to navigate through command history.
Press TAB when typing command name to auto-complete.
[esp32]> help
help
Print the list of registered commands
free
Get the total size of heap memory available
restart
Restart the program
deep_sleep [-t <t>] [--io=<n>] [--io_level=<0|1>]
Enter deep sleep mode. Two wakeup modes are supported: timer and GPIO. If no
wakeup option is specified, will sleep indefinitely.
-t, --time=<t> Wake up time, ms
--io=<n> If specified, wakeup using GPIO with given number
--io_level=<0|1> GPIO level to trigger wakeup
join [--timeout=<t>] <ssid> [<pass>]
Join WiFi AP as a station
--timeout=<t> Connection timeout, ms
<ssid> SSID of AP
<pass> PSK of AP
[esp32]> free
257200
[esp32]> deep_sleep -t 1000
I (146929) deep_sleep: Enabling timer wakeup, timeout=1000000us
I (619) heap_init: Initializing. RAM available for dynamic allocation:
I (620) heap_init: At 3FFAE2A0 len 00001D60 (7 KiB): DRAM
I (626) heap_init: At 3FFB7EA0 len 00028160 (160 KiB): DRAM
I (645) heap_init: At 3FFE0440 len 00003BC0 (14 KiB): D/IRAM
I (664) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM
I (684) heap_init: At 40093EA8 len 0000C158 (48 KiB): IRAM
This is an example of ESP-IDF console component.
Type 'help' to get the list of commands.
Use UP/DOWN arrows to navigate through command history.
Press TAB when typing command name to auto-complete.
[esp32]> join --timeout 10000 test_ap test_password
I (182639) connect: Connecting to 'test_ap'
I (184619) connect: Connected
[esp32]> free
212328
[esp32]> restart
I (205639) restart: Restarting
I (616) heap_init: Initializing. RAM available for dynamic allocation:
I (617) heap_init: At 3FFAE2A0 len 00001D60 (7 KiB): DRAM
I (623) heap_init: At 3FFB7EA0 len 00028160 (160 KiB): DRAM
I (642) heap_init: At 3FFE0440 len 00003BC0 (14 KiB): D/IRAM
I (661) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM
I (681) heap_init: At 40093EA8 len 0000C158 (48 KiB): IRAM
This is an example of ESP-IDF console component.
Type 'help' to get the list of commands.
Use UP/DOWN arrows to navigate through command history.
Press TAB when typing command name to auto-complete.
[esp32]>
```
---
See the README.md file in the upper level 'examples' directory for more information about examples.