Conflict of IO Control
Since IO and other features can be operated both via the cloud (using obniz.js) and locally via Lua, conflicts may occur if the same IO is accessed simultaneously.
By default, obniz.js takes priority. This means that even if an IO is being used by a Lua script, it may be reset depending on the connection status or commands received from obniz.js.
io.retain(io, boolean)
To restrict a specific IO for Lua use only and deny access from obniz.js, use the io.retain() function.
In the following example, IO 0 is set to Lua-exclusive mode:
io.retain(0, true);
When an IO is set to Lua-exclusive mode using the function above, it behaves as follows:
- Access from obniz.js is completely disabled.
- The IO state is maintained (not reset) even if the internet connection is lost.
It is highly recommended to secure the IOs you intend to use in Lua by calling io.retain() beforehand.
About Peripherals
In addition to GPIO (io), features such as uart and spi are also shared resources.
Unlike GPIO, these peripherals automatically become Lua-exclusive as soon as they are accessed from a Lua script.